While in Wally World yesterday I noticed Mobil 1 0W-30 and 0W-40 motor oil. The bottle recommended it for cars that call for 5W-30 or 10W-30 motor oil. Has anyone had any experience with this oil weight in a Fiero or any other type of car and of so was there any advantage or is it only good for vehicles in frigid areas? Thanks
Thin oil like that is probably only really useful for newer motors where tolerances are quite low by design. On an old motor like a 60V6, you really aren't going to win anything.
If your engine can maintain proper oil pressure and volume with the 0W oil, you'll probably see a tiny increase in fuel economy. If your engine can't maintain proper oil pressure though, with the lighter oil, you should stick to the heavier oil.
Of course, the only way you'll know if it'll provide any benefit to you, is if you buy it and use it. Like was already said though, the 2.8 and iron duke weren't built to the same tolerances that current engines are, so it's probably not worth bothering with, unless you've got a 3800, Ecotec, LSx, etc… swap in your car.
0W only affect cold to "freezing" engines. Mainly Weather Below 32°F. As soon as the engine is warm to hot, the xW doesn't matter.
In the real world, I doubt anyone could see a difference between 5W and 0W. Maybe in winter, weather below 0°F and engine never or very slow to warm up. (Likely that car have bigger problem... like Bad Tstat stuck open. etc.) 0W was made to keep Car makers CAFE numbers up to meet NHTSA/EPA regs. Every tiny faction of a point matter to GM and others. Failing CAFE quotas mean big money to car makers.
See my Cave, Oil Sensor Oil Weight, Table is old but give you about same data.
CAFE, google: cafe car regulation
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
I think Mobil claims like a 2% increase in fuel economy. If the engine can maintain oil pressure I think it would be fine.
While these engines have much larger tolerances than new engines (especially given wear and age), they were also designed for oil that wasn't nearly as good. Modern oil, especially a high quality synthetic, is going to provide much more protection than 1980's oil. (The only exception to this might be the flat tappets and the lack of zinc).
0W only affect cold to "freezing" engines. Mainly Weather Below 32°F. As soon as the engine is warm to hot, the xW doesn't matter.
That's actually not exactly true. Because of the additives that create a multigrade oil, the curve between Xw and wY varies. The Xw is measured at 75 degrees, the wY is measured at 212 degrees. Remember this is oil temp and not ambient temp - the point is that 0w oil has an effect even in Southern California on startup wear (in theory). Since engine temps are not static - you won't be at exactly 212 degrees all the time - the curve that exists between the first number and the second number will play into what happens during normal operation. Especially for those people running crazy 195 degree fan switches... eg, a 0w-30 oil at 195 degrees will have a different effective viscosity than a 10w-30 oil at 195 degrees. The exact effects are largely unknown to consumers, but some manufacturers do publish them. )You will generally also find that big wY numbers yield better results at extreme engine temps.)
A related consideration is the viscosity index improvers (VIIs) employed in these oils. A 0w-50, for example, will have some crazy VIIs that a 10w-30 will not. These can be a net positive or a net negative depending on how you look at them. VIIs can reduce the lubricity of oil, so big multigrade oils may be less "good" than narrow ones. Related, since combustion byproducts, heat, and time break down oil viscosity, oil with quality VIIs can be more resistant to long term wear or worn engines.
It's a bloody crapshoot, of course. There is no universal right answer. Like Dobey says, there is no harm in trying one. If it works for you, great. If not, go back to Castrol GTX.
Those 0W30 oils are too thin for a boosted or racing engine to provide long service life. I use 15W50 Mobil One exclusively. The heavier oil provides a better cushion between moving parts and superior wear resistance than thin oils. The manufacturers use thin oils to help meet federal gas mileage standards and because they do not want your engine to last 250,000 miles. I've used Valvoline Racing oils and Mobil One 15W50 for years and on the one engine block that I decided to rebuild ( after 249K miles) the cylinder taper was still within specifications that a simple hone, new rings and bearings was all that was required.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
There is zero science in what you've just said. Without knowing the actual VI or VIIs or additive package of oil in question you cannot make useful statements like that. The chemistry separating a 0w, 5w, 10w and a 20w, 30w, and 40w oil could be so slight as to be insignificant. You cannot make such statements about oil in general based solely on stated grades. The SAE tests which categorize oils are simply not that informative. Additionally, a Group IV 0w-30 would have entirely different properties from a hydrocracked Group III oil or conventional Group II or Group III oil of the same stated viscosity. A Group IV 0w-30 could offer better and longer lasting protection than the best 15w-50 conventional oil on the planet. You should also check your facts regarding the transition from older, thicker oils to newer, thinner oils. While it's true fuel economy plays a significant part in the transition, the other component in play is that the VIIs employed in making big-spread multigrade oils like the 15w-50 you specifically mention is that when the VIIs wear out they make sludge. Manufacturers are moving to smaller spread oils like 0w-20 to get away from the sludge problem that plagued newer motors beginning about 15 years ago.
There is a lot more to do with oil than "bigger is better." Bigger is only better from one angle: It's thicker. Bigger also creates startup wear, economy losses from the oil pump, friction from moving parts, and the potential for sludge. You've entirely left that out of your statement. You've also failed to account for the base oil and the quality and quantity of additives. These are all hugely important factors when determining what is "good" and what is "bad."
Obviously, you do what works for you but anecdotes don't equal science.
[This message has been edited by thesameguy (edited 05-27-2015).]
There is zero science in what you've just said. Without knowing the actual VI or VIIs or additive package of oil in question you cannot make useful statements like that. The chemistry separating a 0w, 5w, 10w and a 20w, 30w, and 40w oil could be so slight as to be insignificant. You cannot make such statements about oil in general based solely on stated grades. The SAE tests which categorize oils are simply not that informative. Additionally, a Group IV 0w-30 would have entirely different properties from a hydrocracked Group III oil or conventional Group II or Group III oil of the same stated viscosity. A Group IV 0w-30 could offer better and longer lasting protection than the best 15w-50 conventional oil on the planet. You should also check your facts regarding the transition from older, thicker oils to newer, thinner oils. While it's true fuel economy plays a significant part in the transition, the other component in play is that the VIIs employed in making big-spread multigrade oils like the 15w-50 you specifically mention is that when the VIIs wear out they make sludge. Manufacturers are moving to smaller spread oils like 0w-20 to get away from the sludge problem that plagued newer motors beginning about 15 years ago.
There is a lot more to do with oil than "bigger is better." Bigger is only better from one angle: It's thicker. Bigger also creates startup wear, economy losses from the oil pump, friction from moving parts, and the potential for sludge. You've entirely left that out of your statement. You've also failed to account for the base oil and the quality and quantity of additives. These are all hugely important factors when determining what is "good" and what is "bad."
Obviously, you do what works for you but anecdotes don't equal science.
I've read literature supporting both what you and Dennis have said. As far as the 195 degree thermostat is concerned, it's important to note that the engine oil at operating temperature without a cooler runs hotter than the engine coolant and very likely is running at least 200 plus degrees given my experience with having run oil temp gauges and the fact that some engines have oil coolers that use the engine coolant to cool the oil as well as get it to operating temperature quickly. It's highly unlikely that the engine oil is running much less than 212 if at all in any car during the Summer so it's not unreasonable to rule the first viscosity index number nearly completely out at operating temps.
What I have found is that the newer engines appear to be running much tighter bearing clearances than ever before and need a thin oil for quick flow and the implementation of VVT has it's needs as going to a much thicker viscosity index than manufacture spec in some of these engines from what I have read can interfere with it's function/calibration. You're both right in my opinion depending on the circumstance. I do understand that the harder you intend to run an engine, the more useful a higher viscosity index can be. The thinner the oil, the less bearing protection you have as the temps go up.
I would not use a 0WX motor oil in an older motor having wiped bearings in a newer motor using 0W15. It's about more than oil pressure, you can tighten your bearing clearances until it's in excess of 100 psi but it will not take much rpm to teach you a lesson in the need for sufficient oil flow over the bearing surfaces to go with that pressure.
I say just use a good quality oil in the recommended dosage or go a little heavier unless economy and granny driving is your goal.
Originally posted by Joseph Upson:I've read literature supporting both what you and Dennis have said. As far as the 195 degree thermostat is concerned, it's important to note that the engine oil at operating temperature without a cooler runs hotter than the engine coolant and very likely is running at least 200 plus degrees given my experience with having run oil temp gauges and the fact that some engines have oil coolers that use the engine coolant to cool the oil as well as get it to operating temperature quickly. It's highly unlikely that the engine oil is running much less than 212 if at all in any car during the Summer so it's not unreasonable to rule the first viscosity index number nearly completely out at operating temps.
I'd say that's all within reason, but of course your summer and my summer could be very different and driving habits play into it as well. If you are an old lady running around to local shops all day, the engine oil may not stay hot for long and the anti-wear of a thinner oil could be the right choice. On the other hand, if you're pounding a race track for hours at a time you probably don't even car about the cold temp - you may not even want a multigrade oil. Point is, blanket statements about what is right without any context aren't helpful for anyone.
quote
What I have found is that the newer engines appear to be running much tighter bearing clearances than ever before and need a thin oil for quick flow and the implementation of VVT has it's needs as going to a much thicker viscosity index than manufacture spec in some of these engines from what I have read can interfere with it's function/calibration. You're both right in my opinion depending on the circumstance. I do understand that the harder you intend to run an engine, the more useful a higher viscosity index can be. The thinner the oil, the less bearing protection you have as the temps go up.
Totally true, but of course you've got a chicken and egg discussion about whether the desire for "narrower" oils to prevent sludge begot tighter bearing tolerances or vice versa. What is clear is that tightening emissions standards around Y2K resulted in mountains of motors sludging up (noteworthy being Toyota, Audi, and Saab) and subsequent recommendations for those narrower oil ranges. The only things I can look at for evidence would be motors that have been in production for a long time, across that Y2K threshold, and especially those (as you point out) that have VVT features. You could look at Honda, Toyota, BMW, or Porsche for such motors, and you'll find examples of manufacturers sticking with thicker oil and manufacturers switching to thinner. Toyota's 2ZZ motor would be an example of the former. That motor just won't run right on anything thicker *or* thinner than it was designed for!
IMHO, the core thing to remember is that crappy oil with a bunch of VIIs isn't doing anyone any favors. That is poor lubrication coupled with the potential for long-term sludge issues. A super high quality oil, like a Group IV synthetic, coupled with fewer VIIs result in superior lubrication coupled with excellent long-term durability. For the "right" answer you need to look at how the car is used, how the motor was built, and what your maintenance habits are going to be. If you're not doing that, you might as well flip a coin, or better yet, just stick with the manufacturer's recommendation. Choosing an oil based simply on how much heat it can tolerate isn't doing you any favors.
quote
I would not use a 0WX motor oil in an older motor having wiped bearings in a newer motor using 0W15. It's about more than oil pressure, you can tighten your bearing clearances until it's in excess of 100 psi but it will not take much rpm to teach you a lesson in the need for sufficient oil flow over the bearing surfaces to go with that pressure.
Although I have yet to have a problem running thin oil on anything, your logic is sound. I ran M1 0w-40 on my 1990 Saab for years and years pushing very high boost without an issue. I used that oil primarily because I had it around for my Alfa 164Q. I've since sold the Alfa and the Saab got wrecked, now everything (including the Fiero, a '62 Falcon, and a '67 Cadillac) gets 5w-40 Group IV oil. All good for many years.
Lots of discussion about this.... let me ask, is there a shortage of 5w-30 oil? If not, just use what GM recommended, at least that is what I have done. I use what the manufacturer recommends (based on the manual). I do run synthetic though, but with the correct weight.
Lots of discussion about this.... let me ask, is there a shortage of 5w-30 oil? If not, just use what GM recommended, at least that is what I have done. I use what the manufacturer recommends (based on the manual). I do run synthetic though, but with the correct weight.
There might be.
I think the discussion was about the availability of a 0w oil and an oil manufacturer suggestion it was a suitable & superior substitution for 5w-30.
FWIW, I tend to agree. If you don't have a specific thing you're trying to accomplish that the factory recommendation is unable to meet, stick with the factory recommendation.
The only reason I don't is because stocking 10 different types of oil for 10 different cars would be really annoying. 5w-40 hits all the bullet points and saves shelf space.
I've been running 10/30 oil in my 87 GT since I bought the car 28 years ago. The car has 155,000 miles on it and I've had no issues with the engine. It doesn't use any oil between changes. Most new cars request the use of 0-30 or 0-40w oils.
I've been running 10/30 oil in my 87 GT since I bought the car 28 years ago. The car has 155,000 miles on it and I've had no issues with the engine. It doesn't use any oil between changes. Most new cars request the use of 0-30 or 0-40w oils.
Most new gasoline-only cars spec 5w30. So far, the only ones I've seen that spec 0w oils, are hybrids. The Gen V SBC (LT1/LT4) specifies 5w30 dexos1 synthetic blend for normal daily driving, and allows for 0w30 in extreme cold climates (less than -20F ambient temperatures), and recommends 15w50 Mobil 1 for track/competitive driving.
5w-20 is also quite popular amongst lower end cars. Ford, Honda, and Chrysler all spec it. Nissan and Toyota I believe are both doing 0w-20 now. GM seems to have largely stuck with 5w-30. A lot of higher-end cars like Mercedes, BMW, and Audi recommend 5w-40 or 0w-40 except in their higher performance motors where, like Porsche, they recommend 10w-50 or 10w-60. All the Euros specify synthetic and nothing but. Most have very long change intervals - 10k or 15k. I don't know what Acura, Lexus, and Infiniti recommend - probably the same Xw-20 their lesser cousins use, but it'd be funny if they specified full synthetic on the same motors. ROFL.
There is zero science in what you've just said. Without knowing the actual VI or VIIs or additive package of oil in question you cannot make useful statements like that. The chemistry separating a 0w, 5w, 10w and a 20w, 30w, and 40w oil could be so slight as to be insignificant. You cannot make such statements about oil in general based solely on stated grades. The SAE tests which categorize oils are simply not that informative. Additionally, a Group IV 0w-30 would have entirely different properties from a hydrocracked Group III oil or conventional Group II or Group III oil of the same stated viscosity. A Group IV 0w-30 could offer better and longer lasting protection than the best 15w-50 conventional oil on the planet. You should also check your facts regarding the transition from older, thicker oils to newer, thinner oils. While it's true fuel economy plays a significant part in the transition, the other component in play is that the VIIs employed in making big-spread multigrade oils like the 15w-50 you specifically mention is that when the VIIs wear out they make sludge. Manufacturers are moving to smaller spread oils like 0w-20 to get away from the sludge problem that plagued newer motors beginning about 15 years ago.
There is a lot more to do with oil than "bigger is better." Bigger is only better from one angle: It's thicker. Bigger also creates startup wear, economy losses from the oil pump, friction from moving parts, and the potential for sludge. You've entirely left that out of your statement. You've also failed to account for the base oil and the quality and quantity of additives. These are all hugely important factors when determining what is "good" and what is "bad."
Obviously, you do what works for you but anecdotes don't equal science.
Then if its not science, why do all race cars use heavier grade oils going all the way to 70W in top fuel cars? Point is heavier weight oil (to a point) provides a safety cushion against wear on high output race engines. My experience and the experiences of friends has confirmed it on street engines as well. As for sludge my oil looks super clean to me when I change it.
[This message has been edited by Dennis LaGrua (edited 06-01-2015).]
Originally posted by Dennis LaGrua: Then if its not science, why do all race cars use heavier grade oils going all the way to 70W in top fuel cars? Point is heavier weight oil (to a point) provides a safety cushion against wear on high output race engines. My experience and the experiences of friends has confirmed it on street engines as well. As for sludge my oil looks super clean to me when I change it.
Top fuel cars also change bearings every couple of runs, and have enough spare parts in the trailers for multiple spare engines. Race engines are also built for different tolerances and require much higher octane spec fuel than street cars as well. Street gasoline engines are starting to creep up to higher compression ratios close to where N/A race engines run, though. The new LT1 is 11.5:1 for example. The amount of stress inside a top fuel engine would destroy lighter weight oils pretty fast. Using 15/20w50 in a street engine is not going to make your engine last longer. If they didn't want your engine to last 250K miles, they wouldn't be handing out 100K mile warranties on all the new engines. If you take proper care of a street prepped engine, it will last well more than 250K miles. A race engine won't. Those differences have nothing to do with the oil itself.
Then if its not science, why do all race cars use heavier grade oils going all the way to 70W in top fuel cars? Point is heavier weight oil (to a point) provides a safety cushion against wear on high output race engines. My experience and the experiences of friends has confirmed it on street engines as well. As for sludge my oil looks super clean to me when I change it.
quote
Originally posted by thesameguy:There is a lot more to do with oil than "bigger is better." Bigger is only better from one angle: It's thicker. Bigger also creates startup wear, economy losses from the oil pump, friction from moving parts, and the potential for sludge. You've entirely left that out of your statement. You've also failed to account for the base oil and the quality and quantity of additives. These are all hugely important factors when determining what is "good" and what is "bad."
What works for a race engine has almost nothing to do with what works on a street engine for exactly the reasons I've stated. As for sludge, it collects in places that do not drain naturally, so of course you don't see it on an oil change. The only way you get sludge out of an engine is by tearing it down. The only way to know if the VIIs have failed is by having it analyzed. On a race motor, where oil needs to last one day or one weekend it's probably not a concern. But on a street motor that may not see 100% reliable oil changes for a variety of reasons and probably isn't as clean internally as a race motor, trading something you may not need (a bigger cushion) for all the things you do want (better economy, better startup protection, less potential for sludge) seems like a bad trade. Recommending 15w-50 because you race with it makes no more sense that recommending NT01s or 800 lb in springs. There is a lot more to consider for street vehicles than heat resistance and grip.
[This message has been edited by thesameguy (edited 06-01-2015).]
Provide all the theory that you want but 15W50 synthetic IS working on my street/strip engines. The wear patterns on my engines seem to disagree with your theory. My last car went 198,000 miles and was running perfect, not smoking, provided consistent mileage or burning oil when I sold it. What about the 250,000 mile engine that we broke down and measured up who's cylinder bores were still within factory specs as was the crankshaft? That's good enough proof that makes sense to me. Do you have more than words and concrete evidence to show that 15W50 doesn't work? As for Dobey's comment that parts in top fuel engines are constantly being replaced. That's true but without the superior protection and film strength of heavier grade oils those engines won't last for a single run. A 70w oil may be too heavy for a daily driver as it doesn't flow well but 15W 50 seems just right, maybe not for optimal mileage but for limiting wear. Use what you want, I've found something that works on my engine. If you discount actual user experiences there is far more to be found.
[This message has been edited by Dennis LaGrua (edited 06-02-2015).]
Originally posted by Dennis LaGrua: Provide all the theory that you want but 15W50 synthetic IS working on my street/strip engines. The wear patterns on my engines seem to disagree with your theory. My last car went 198,000 miles and was running perfect, not smoking, provided consistent mileage or burning oil when I sold it. What about the 250,000 mile engine that we broke down and measured up who's cylinder bores were still within factory specs as was the crankshaft? That's good enough proof that makes sense to me. Do you have more than words and concrete evidence to show that 15W50 doesn't work? As for Dobey's comment that parts in top fuel engines are constantly being replaced. That's true but without the superior protection and film strength of heavier grade oils those engines won't last for a single run. A 70w oil may be too heavy for a daily driver as it doesn't flow well but 15W 50 seems just right, maybe not for optimal mileage but for limiting wear. Use what you want, I've found something that works on my engine. If you discount actual user experiences there is far more to be found.
The problem with your claim is that all you have is a theory, and are simply spouting anecdote (words), to suggest that 15w50 is somehow better than 10w30, 5w30, etc… You have no concrete evidence or scientific study which proves your theory. You have anecdotes which suggest that the oil you are using isn't harmful to your engine. Your anecdote doesn't prove that the oil you are using is somehow better. Of course you can run race spec oil in a street car engine. That doesn't necessarily mean that it is performing better.
To present your tale as a valid scientific study, you must have multiple engines of the exact same construction and tolerance specs, some being the "control group" running the OE recommended 5w30, and others in the variable group running the 15w50 you claim is better. They must all see the same amount of running hours, through the same RPM ranges, and work loads. You can then compare physical wear, to see which is better in that respect. You must also however, compare power output, and brake specific fuel consumption differences, as internal combustion engines are complex machines with many factors which may determine what solution is better for one person or another.
GM certainly has much more data on these matters than you obviously do, and run many of their engines for a 24 hour break-in/test period on an engine dyno, before they even go in a car or get shipped out in a crate, and specify oil weight and viscosity values different than what you are suggesting is somehow superior to their recommendation. While the 2.8 and 2.5 probably didn't go through such testing back in the 80s, before being dropped in the Fiero chassis, as long as you don't beat the ever living crap out of the engine, and maintain it properly with required fluid changes at appropriate intervals, the engines will last well over 250K miles, with the specified 5w30.
FYI... 200k+ on '88 2.8 running 5w-30. Same for Aztek... 178k on 5w-30 (fram filters even... for those who think they are bad). Even had intake and head gasket coolant leaks on that engine. I think changing oil is more important than oil specifics for most street engines.
Unless you regularly start your Fiero's 2.5 or 2.8 in temps well below freezing there woudl be no real benefit from going from 5w to 0w IMO. If you have a slow leak however it could leak more at room temp with the thinner 0w.
[This message has been edited by 2.5 (edited 06-02-2015).]
5w-20 is also quite popular amongst lower end cars. .
Xw-20 would not be safe for a 2.5 or 2.8 because it is too thin at operating temp. For the most part they started using it for mpg reasons in newer cars IMO.
Xw-20 would not be safe for a 2.5 or 2.8 because it is too thin at operating temp. For the most part they started using it for mpg reasons in newer cars IMO.
Totally - like someone said way back up there running such an oil on an old motor would *probably* be asking for problems. Maybe not, new oil is pretty good, but certainly not worth the risk. Unless there's a specific reason not to - application, history, etc. - I'd say with confidence use the oil GM specified from a reputable manufacturer. Again, the only reason I personally use anything different is because what I have isn't worse. Group IV 5w-40 is probably winning me nothing on the Fiero, but it's saving me a trip to the auto parts store. It's worth the extra $10 per oil change to not leave the house. :P
I accidentally put 5w20 in a 4.3 once and could hear it ticking, after draining it and putting 5w30 in the tick was gone. Just wanted to clarify its not about the quality in this case but the viscosity.
[This message has been edited by 2.5 (edited 06-03-2015).]
While researching another subject I discovered some interesting relevant info that should put this to rest.
There was reference made to sludge, something I have had no experience with even in my poorly maintained domestic motors but observed a few times in imports which were cited.
It appears the reason the sludge problem was mainly mentioned in imports is because they are often the pioneers in new engine technology/changes; low viscosity oil use, MLS head gaskets, etc.
Well, the said cause of oil sludge in what I read yesterday is combustion gases contaminating the crank case, oxidizing the oil causing it to sludge depending on the extent of contamination.
What likely makes it more common in imports is this; the use of low tension piston rings in production motors to reduce internal friction forces and increase fuel economy, combined with low viscosity oil.
That can explain why the Fiero had a 7000 mile oil change interval and many of your small engine late model cars a 3000 mile oil change interval despite the improved quality of motor oil. I've happened across a few late model four cylinders that by the time they hit the oil change interval the oil is filthy and near a quart low which is evidence of the above suspicion as the thin oil can get past low tension rings easier (as well as combustion gases) to be burned. There are a number of complaints of some newer cars using oil, one in particular the VW.
GM uses thinner rings now than what they did in the Fiero.
I believe today's shelf oils are pretty close in the contained basic additives so it is not unreasonable to expect the numerical viscosity to be a consistent measure of increasing or decreasing viscosity, because my engine is also much quieter when 5W30 is replaced with 15W50 which I usually run for high compression and boost.
I doubt anyone leaves oil in their cars long enough anymore for sludging to occur.
I think if you look around you'll find that failed VIIs are also oil contaminants which cause sludge. This is not obscure theory, it's reproducible science. Here is one account:
[quote]After a period of time shearing, the oil will lose it's ability to hold up to the same flow as before since the VI Improvers are breaking down causing the oil to thin down in grade. Once this happens, there is less film strength between the mating surfaces so it doesn't take as much for the oil to shear, therefore creating more heat which attacks the base oil even more and then starts to cause the oil to thicken up due to the excessive levels of heat and the broken down VI Improvers become a contaminant which added to the existing oil will continue to thicken and ultimately cause sludge if not changed in a reasonable time.. [/quote[
Long oil change intervals combined with low-quality base oils stocked with VIIs to get to crazy spreads like 15w-50 causes this scenario to unfold reliably. It's why all the European brands with long oil change intervals specify synethic oil, and why all the hi-po Euro motors spec only Group IV (and not fake Group III) oils. Because such high quality oils do not require the same quantities of BS polymers to achieve the same ratings you don't end up with components of your oil ending up working against it.
Yes, blowby contaminants coupled with insufficient PCV systems resulted in a lot of sludge for a lot people, but it doesn't change the fact that the *science* shows that high VII loadouts work against you, if not sooner than later for sure. This problem is why a) modern engines are increasingly designed to work with oils that do not require them, and b) nobody makes a production engine which specs them. Everybody from AMG to Ford specs full synthetic 5w-50s (and similar) to protect their motors, because a 15w motor oil isn't doing anyone any favors ever. Well, except people who have old, worn engines.
But, listen, I am checking out of this thread. The bases have been covered, the information presented. If folks want to do weird stuff because it makes them happy that's cool with me.
Are there 5w40 oils that are not full synthetic? I like the dynamic of the range, but full synthetic was prone to leaking on the vehicle I primarily would use it in.
I think if you look around you'll find that failed VIIs are also oil contaminants which cause sludge. This is not obscure theory, it's reproducible science. Here is one account:
[quote]After a period of time shearing, the oil will lose it's ability to hold up to the same flow as before since the VI Improvers are breaking down causing the oil to thin down in grade. Once this happens, there is less film strength between the mating surfaces so it doesn't take as much for the oil to shear, therefore creating more heat which attacks the base oil even more and then starts to cause the oil to thicken up due to the excessive levels of heat and the broken down VI Improvers become a contaminant which added to the existing oil will continue to thicken and ultimately cause sludge if not changed in a reasonable time.. [/quote[
Long oil change intervals combined with low-quality base oils stocked with VIIs to get to crazy spreads like 15w-50 causes this scenario to unfold reliably. It's why all the European brands with long oil change intervals specify synethic oil, and why all the hi-po Euro motors spec only Group IV (and not fake Group III) oils. Because such high quality oils do not require the same quantities of BS polymers to achieve the same ratings you don't end up with components of your oil ending up working against it.
Yes, blowby contaminants coupled with insufficient PCV systems resulted in a lot of sludge for a lot people, but it doesn't change the fact that the *science* shows that high VII loadouts work against you, if not sooner than later for sure. This problem is why a) modern engines are increasingly designed to work with oils that do not require them, and b) nobody makes a production engine which specs them. Everybody from AMG to Ford specs full synthetic 5w-50s (and similar) to protect their motors, because a 15w motor oil isn't doing anyone any favors ever. Well, except people who have old, worn engines.
But, listen, I am checking out of this thread. The bases have been covered, the information presented. If folks want to do weird stuff because it makes them happy that's cool with me.
I get the impression it is more important that everyone agree with you than understand the detailed info you're providing which is appreciated. The science you refer to has to be applicable to everyday driving conditions. Just bearing out the possible pitfalls and weak points in various lubricants in a controlled scientific setting that many vehicles rarely or may never see is not sufficient. Few now days resort to long oil change intervals as you identified above and many change their oil at what I consider wastefully short intervals.
You're providing useful info, don't quit due to slow acceptance or understanding of what you present. Some, including myself have not had a problem at all while going against the grain and seeing is believing. I don't know bob the oil guy and would not trust his theory over a manufacturer as I have not seen the problems mentioned in any of the many engines I have built and used.
I visited Mobil 1s site for a less dense explanation and found that 0W40 at least in Mobil 1 has the greatest viscosity index(VI) at 185 and 15W50 has the greatest Viscosity (cSt) at 100 deg C. The short and sweet here is this:
Viscosity index and change in viscosity work inversely, the lower the VI, the greater the change in viscosity, the higher the VI the lower the change in viscosity and therefore have more consistency in viscosity.
0W40 VI= 185, viscosity at 100C= 13.5, at 40C= 75 Porche, BMW, VW approval 15W50 VI= 160, viscosity at 100C= 18, at 40C= 125 no OE listings 5W50 VI= 180, viscosity at 100C= 17.5 at 40C= 108 Porche, BMW, VW, Lexus approval
In a simple approach, the lower the possible cold weather temps in your location, the greater the benefit of a 0-5W oil. The harder you run your motor, the greater the benefit of a high VI oil. So it appears the 0 and 5W50 oils will better serve my application than the 15W50 I have used in the past. I'm runnng 5W50 now.
"A 5W-30 motor oil performs like a SAE 5 motor oil would perform at the cold temperature specified, (Startup)...but still has the SAE 30 viscosity at 210° F (100° C) which is engine operating temperature. This allows the engine to get quick oil flow when it is started cold verses dry running until lubricant either warms up sufficiently or is finally forced through the engine oil system. The advantages of a low W viscosity number is obvious. The quicker the oil flows cold, the less dry running. Less dry running means much less engine wear."
The problem with motor oils is that its very difficult to really observe the differences between them. People love making favorites but are susceptible to marketing. I personally "like" Mobil 1 - but do I have any real evidence that it's a shred better than Castrol GTX? No. Do I think it protects my motor better? Yes. Do I think it helps fuel economy a little bit? Yes. But I have no way to measure it. But it makes me feel warm and fuzzy inside when I'm pouring the oil out of that nice silver Mobil 1 bottle.
Generally speaking, IMO, I would stick to the recommended oil weight by the manufacturer, who obviously did their homework and had the tools to properly test it. A thicker oil may provide more "cushion" at high temperatures but it also may flow so poorly at low temperatures that some areas are starved for lubrication. What may be providing improved protection of the cylinder walls from piston scuffing may also be causing extra wear on the cam bearings. It's hard to know for sure just by using it. The engine may sound quieter but may also be suffering extensive wear on parts unseen.
0W-30 is interesting though because Mobil 1 specifically says it can be used where 5w-30 is recommended. To me that means that the film strength and protection is equivalent to at least a conventional 5w-30 oil but with better flow characteristics.
[This message has been edited by masospaghetti (edited 06-04-2015).]
I follow the manufacturer's weight recommendation. No reason to try and outsmart the company that build the engine and warrantied it. People will do what they want though....
quote
Originally posted by masospaghetti:
Generally speaking, IMO, I would stick to the recommended oil weight by the manufacturer, who obviously did their homework and had the tools to properly test it. A thicker oil may provide more "cushion" at high temperatures but it also may flow so poorly at low temperatures that some areas are starved for lubrication. What may be providing improved protection of the cylinder walls from piston scuffing may also be causing extra wear on the cam bearings. It's hard to know for sure just by using it. The engine may sound quieter but may also be suffering extensive wear on parts unseen.
0W-30 is interesting though because Mobil 1 specifically says it can be used where 5w-30 is recommended. To me that means that the film strength and protection is equivalent to at least a conventional 5w-30 oil but with better flow characteristics.
In my opinion 0w 30 would almost always be better than 5w30 because it would flow better than 5w30 at startup and the same as 5w30 at operating temp.
Fuuuuuu.... I can't believe I came back. Slow day at the office.
quote
Originally posted by Joseph Upson: In a simple approach, the lower the possible cold weather temps in your location, the greater the benefit of a 0-5W oil. The harder you run your motor, the greater the benefit of a high VI oil. So it appears the 0 and 5W50 oils will better serve my application than the 15W50 I have used in the past. I'm runnng 5W50 now.
This is exactly right, but there is more in play. There is a curve that exists connecting the first number to the second number, and that curve extends before the first number and beyond the second number. The SAE tests pick two points along that curve and that is how engine oil is graded. There are two important facts about this detail: First, an oil may have performance characteristics at 75* F that cause it to be a 5w oil, but performance characteristics at 76* F that cause it be a 10w oil. The SAE doesn't care about that one degree, the oil is rated at 75* and that's that. As a result, what separates any two neighbor grades could be slight or could be significant, you don't know. Secondly, because the curve extends in all directions there are performance characteristics that *could* be more relevant to your situation than the SAE grade. If you live in Alaska or race your car every day, who cares about 75 degrees or 212 degrees? Not you, neither of those temps affect you.
The next consideration is that modern engine oil contains additives for anti-wear, detergents, and viscosity index improvers. A big package which to a large degree is probably more significant than the actual grade, within reason. That cheapo oil you buy in an emergency at the gas station won't hold a candle to a quality name brand oil in terms of its ability to protect a motor, clean a motor, and maintain its characteristics over the long haul. These days, auto manufacturers are VERY wise to these facts which is why suddenly 10w-30 isn't the go-to it once was. Realizing that you can make a very thin oil like 0w-20 perform exactly as well as a 10w-30 while improving fuel economy and reducing leftovers (sludge, deposits, etc.) is huge. It's all win, no loss. Bear in mind 0w-20 is just an example - the additives, detergents, and VII consideration exists in all oil, period.
Finally, and maybe most importantly, is the base oil. Oil is grouped in four categories by the API appropriately called I, II, III, and IV. I, II, and III are all natural oil, dinosaur oil as it were. Group IV oils are man-made oils, called polyalphaolefins (PAOs). There is technically a fifth group, which is simply all oils that can't be placed into one of the other groups. What separates one group from the other is the quantity of saturates (higher group, higher percentage of saturates), quantity of sulphur (higher group, less sulphur), and base viscoscity. Group III is a special group, because to produce Group III oil, an oil goes through a process called hydrocracking (application of pressure and heat). The longer an oil is hydrocracked, the purer and better it becomes. Around a decade ago, *domestically* Castrol made the point that if you hydrocrack a Group III oil long enough it becomes virtually indistinguisable from a man-made Group IV oil. Thus, *domestically*, some Group III oils are labeled as synthetics. That is only true here, that technicality does not fly in Europe.
What is important about the base oil is that any oil can be made to perform like another oil with the right quantity of additives. But those additives eventually break down and either stop doing their job, or start working actively against the oil. See that "oil shear" article I posted above for an example. So your 10w-30 Group II oil might only behave itself for X miles, whereas a 10w-30 Group IV oil - requiring fewer additives to do its job - might do the same job for 2x miles. Worse, when your Group II fails it might fail catastrophically, whereas the Group IV oil might only do less good. Additionally, because PAO Group IV oils are of an innately highly quality, they will tend behave in predictable ways on all sides of the SAE grading curve.
The point of all of this is that shopping on grade is like shopping on engine displacement. It's a factor, but it's not the whole story. A 1.6l Ecoboost Fiesta will tromp a 2.5l Iron Duke Fiero despite the Duke's clear displacement superiority. A 10w-30 Group IV oil is likely (not guaranteed) to do better, longer than a 5w-40 Group II oil. A high quality Mobil oil is likely to behave itself more reliably than an inexpensive Autozone oil. All these reasons are why I said originally "15w-50" is not an answer. "Mobil 1 15w-50" could be an answer - I mean, I'd disagree with it but at least it's taking into account some actual variables. Related, the consideration with a 5w-50 oil would be the VIIs necessary to make a very thin oil stay thick at high temperatures. If it's same shady Group II oil with a huge quantity of polymers to get that spread, you are going to want to be VERY on-time with oil changes and understand that if you push the oil too far it will fall apart (literally) and work against you. On the other hand, if it's a quality Group IV oil with an innate temperature resistance you are in much better shape. Bear in mind with Mobil 1, unless it says European on it, you do not know what you are getting. Since the Castrol lawsuit, Mobil 1 dumped a lot of their Group IV oils domestically and started selling cheaper Group III oils. It is why I buy German (Lubromoly) or French (Motul) oils exclusively these days. At least I know what I'm getting.
quote
Originally posted by masospaghetti: The problem with motor oils is that its very difficult to really observe the differences between them. People love making favorites but are susceptible to marketing. I personally "like" Mobil 1 - but do I have any real evidence that it's a shred better than Castrol GTX? No. Do I think it protects my motor better? Yes. Do I think it helps fuel economy a little bit? Yes. But I have no way to measure it. But it makes me feel warm and fuzzy inside when I'm pouring the oil out of that nice silver Mobil 1 bottle.
Well, a lot can be learned from the MSDS sheets, because they necessarily discuss the base oil and the additive package. Not to a finite degree, but it's better than nothing. You can also gain *some* information from manufacturer certifications. A reputable brand like Mercedes saying "this will protect a Mercedes engine for 10,000 miles" is a good clue as to the nature of the additive package and the durability of the oil. There is certainly some marketing there, but it's a clue at least. My personal opinion is that because there are *so many* variables in play, start with the highest quality base stock you can afford and go from there. You can also find a lot more interested people on BITOG who've already done that for you.
quote
Originally posted by masospaghetti: Generally speaking, IMO, I would stick to the recommended oil weight by the manufacturer, who obviously did their homework and had the tools to properly test it. A thicker oil may provide more "cushion" at high temperatures but t also may flow so poorly at low temperatures that some areas are starved for lubrication. What may be providing improved protection of the cylinder walls from piston scuffing may also be causing extra wear on the cam bearings. It's hard to know for sure just by using it. The engine may sound quieter but may also be suffering extensive wear on parts unseen.
Yeah, what it sounds like is not exactly a scientific measure of anything. Some engines are clattery - thickening up oil until the noise goes away is like covering your ears so you can't hear your own screams. IMHO, if you have a noisy engine and you're concerned your oil isn't doing the job, send a sample off for analysis. They will tell you if there are metal bits breaking off into your oil and then you'll know something is actually wrong and you need to act. These services are not expensive and might save you from long term engine damage *or* needlessly wasting fuel.
quote
Originally posted by masospaghetti:
0W-30 is interesting though because Mobil 1 specifically says it can be used where 5w-30 is recommended. To me that means that the film strength and protection is equivalent to at least a conventional 5w-30 oil but with better flow characteristics.
Like 2.5 said, the lower the first number the better - almost entirely. The considerations would be oil that is too thin to stay in the engine or oil that is too thin to get oil pressure in a reasonable time. These are both measurable things, so, you know, measure them. It does not take long for an engine to get past 75 degrees, and then the discussion is about the viscosity index curve and the additive package.
Originally posted by masospaghetti: Generally speaking, IMO, I would stick to the recommended oil weight by the manufacturer, who obviously did their homework and had the tools to properly test it.
quote
Originally posted by jaskispyder: I follow the manufacturer's weight recommendation. No reason to try and outsmart the company that build the engine and warrantied it. People will do what they want though....
Genrally yes, the manufacturer recommends what they rated the car on because the EPA requires it. Otherwise all sorts of sneaky stuff would go on after testing was complete, like factory oldsmobile engines in chevy cars which surprised some owners way back in the day among other things.
More important here is the fact that many of us are not dealing with factory unmodified cars so stock recommendations are not always sufficient and when power output is increased heat is increased and thus the upgrades are in order.
Maybe, but you'll note 550hp Cadillacs and 600hp Corvettes still use good ol' 5w-30. The ideal is the lightest oil that doesn't fall apart. Anything more is just losses. Again, this is where engine oil analysis is useful. Put some oil in, beat the crap out of your car, send oil in for analysis, and let a microscope tell you whether the oil broke down or didn't.
Maybe, but you'll note 550hp Cadillacs and 600hp Corvettes still use good ol' 5w-30. The ideal is the lightest oil that doesn't fall apart. Anything more is just losses. Again, this is where engine oil analysis is useful. Put some oil in, beat the crap out of your car, send oil in for analysis, and let a microscope tell you whether the oil broke down or didn't.
550 hp Cadillacs and 600 hp Corvettes with 8 cylinders are a lot less stressed out than V6 motors producing that level of power, further more, unlike those factory Cadi's and Vettes putting out that kind of power, our swaps with the exception of a very small few and those are usually over riddnen, do not have electronic throttle bodies and computers that sense risk of drivetrain damage and ease up on the throttle regardless of how hard the pedal is against the floor to prevent it. So quite a bit of upgrading was done to accommodate those stresses, one of which I'm sure is an oil cooler and lets not forget the other special upgrades like titanium rods and everything else to support those power levels that are missing from our swaps.
Maybe, but you'll note 550hp Cadillacs and 600hp Corvettes still use good ol' 5w-30. The ideal is the lightest oil that doesn't fall apart. Anything more is just losses. Again, this is where engine oil analysis is useful. Put some oil in, beat the crap out of your car, send oil in for analysis, and let a microscope tell you whether the oil broke down or didn't.
Actually, if you read the manual for the cars you're referring to, you'll find they have multiple recommendations, depending on how the car is being used. If you drive a new C7 off the lot and straight to a race track, and spend 8 hours driving in circles, then have some issue with the engine, you might find it may not be covered under the warranty, if you didn't perform oil changes to switch to the 15w50 before the track time, and back to 5w30 after for street usage.
