Hey guys, i have a 2.8 v6, simple question, I would like to get a different thermostat? so that my engine will run cooler? What kind of thermostat should i get for this engine to keep the engine running cooler than stock? thanks!
Any other cooling suggestions would be helpful too!
I'm getting my alternate car ready for Run For The Hills. Both coolant rails have slight crushes and the car will quickly overheat at a traffic light in mid 80's temps. Running hard in the mountains, mostly in 3rd and 4th gears can overheat it quickly, so I just came back from picking up a 180 thermostat at Advance Auto.
I'm getting my alternate car ready for Run For The Hills. Both coolant rails have slight crushes and the car will quickly overheat at a traffic light in mid 80's temps. Running hard in the mountains, mostly in 3rd and 4th gears can overheat it quickly, so I just came back from picking up a 180 thermostat at Advance Auto.
Maybe you can explain why having a lower temp thermostat will help you when the coolant is being blocked by dents in the coolant tube.
Does your car run hotter than 195*? If so, going to a lower temp thermostat probably wont help in that regard. Since the standard thermostat opens at 195 and at that point the coolant is flowing thru the system freely. If the engine continues heating up past that point then a change of thermostat won't really change things. All that will happen is that the coolant will start flowing earlier (at 160 or 180 degrees). What happens with my car is that when I am stuck in traffic (on a hot day) the temp raises up well past 220 (according to my gauge) and having a cooler thermostat wouldn't change this. What does help a lot is that I will then turn on AC and thus activate my radiator fan ...at that point the engine cools back down to 190 or so. If you want the engine to run cooler, I think a better bet is to get a fan switch that comes on at a lower temp (the stock one doesn't kick on until 235 degrees....unless you do what I do and turn on the AC which also causes the fan to come on). I think Rodney Dickman carries other fan switches that come on at a more reasonable temp
Maybe you can explain why having a lower temp thermostat will help you when the coolant is being blocked by dents in the coolant tube.
It allows the engine to run at a lower temp. The dents are slight. Not enough to block the flow, but definitely there's some restriction. The 195 thermostat is a restriction to flow, in a sense. The 180 thermostat just lets the coolant flow through to the radiator earlier at a lower temp. My car doesn't overheat at normal driving, but there's enough restriction with the dents and the 195 thermostat that it tends to be a problem in stop and go and under performance driving conditions. Totally removing the thermostat would help even further.
Fieros like the warmer temperatures to run correctly. I expect that running at 180 your MPG will suffer.
In my case, it probably will, but when doing Run For The Hills, I'm not worried about MPG. That[s my reason for changing to the lower temp thermostat. It will get changed back to the 195 thermostat after the event. BUT, even for every day driving, I'd rather pay a little extra for each tank of fuel than to have to pay a big chunk all at once for a cooked engine.
So I just got my temp gauge working a few weeks ago, and I've noticed that driving around town the temp never really gets over 150-160 or so. Is this a cause for concern? It will get up to 220 and engage the fan if I leave it idling in my garage for 15-20 minutes with the decklid closed, so all sensors and the gauge seem to be working properly, but it seems like otherwise it simply never gets hot enough. I do have the A/C running, so I guess that COULD be slowing down the heating process, but my Jeep warms up to 210 within 5 minutes of driving a similar route. It just kind of surprised me after always hearing that Fieros are prone to overheating, and months of not knowing how hot it was getting before I got the gauge working.
So I just got my temp gauge working a few weeks ago, and I've noticed that driving around town the temp never really gets over 150-160 or so. Is this a cause for concern? It will get up to 220 and engage the fan if I leave it idling in my garage for 15-20 minutes with the decklid closed, so all sensors and the gauge seem to be working properly, but it seems like otherwise it simply never gets hot enough. I do have the A/C running, so I guess that COULD be slowing down the heating process, but my Jeep warms up to 210 within 5 minutes of driving a similar route. It just kind of surprised me after always hearing that Fieros are prone to overheating, and months of not knowing how hot it was getting before I got the gauge working.
I'd expect that your temp gauge is not accurate. My 87 and 88 GT both gauges rarely get past the first quarter hash mark when I'm driving. A few times if I get stuck in traffic the gauge will reach the 220 mark and the fan kicks on. My V8 Fiero's gauge reads 20 degrees high, but these are not stock gauges, so it reads 240 a lot of the time.
There are a number of factors involved here, so if I am telling you stuff you already know, sorry. The Fiero computer runs the engine in what is called 'closed loop' operation, and will do so only after some sensors tell the computer the engine is ready. One big factor is temperature. If the engine does not show a certain temperature over a period of time, the car stays in 'open loop', which is to say it runs on a bunch of presets that are not as efficient. The actual temperature needed to switch to 'closed loop' is hard to pin down, but it is somewhere in the 180* to 185* range. The original thermostat was 195*. There is a LOT of coolant in a Fiero, possibly twice as much as your Jeep, so it takes longer to heat it all up.
The gauges in a Fiero are not very accurate. The original switch for the fan was set at 235*. You are seeing yours turn on when the gauge says 220*, so if the switch is still good you have an error of 15* or about 6%. If you add 6% to your normal operating temperature, you get about 170*, so chances are you are driving in open loop until your entire cooling system has warmed up to 180* which may be 15 minutes in the summer, but never happen in the winter.
I lot of people think the Fiero is overheating, when in reality it is running at it's designed-for temperature....which is pretty hot, and you get to sample it quickly as you get out of the car.....something that no other car can offer....
[This message has been edited by Gall757 (edited 09-05-2013).]
In the Fiero V6 there are two sensors that read coolant temperature. One is the sensor that displays the temperature on the gauge. That's the Gauge or Temperature Light sending unit. This actually has no effect on the operation of the engine. It's just a driver information sensor. The other coolant temperature sensor is one that feeds information to the ECM. This is the one that controls open and closed loop operation and feeds information to the fuel injector circuit and gives no information to the driver. It increases or decreases air-fuel ratios dependant upon the temperature it thinks it's reading.
Installing a 180 degree thermostat can cause the engine to run in open loop, thus causing the ECM to richen the air-fuel mixture. That is, if the Coolant Temperature Sensor feeding info to the ECM is working correctly. If it's defective and feeding higher temperature information to the ECM, the engine will run in closed loop (leaner air-fuel ratio) but the actual engine temperature will be lower than required to cause the ECM to go to closed loop if everything were working at optimum.
Now, Commodore-Dude, if you're running your AC while letting the car sit and idle, you won't be getting correct information. If the whole system is working correctly, the cooling fan runs at all times the AC system is active, so that's not an effective way of checking accuracy of the gauge or sensors. The coolant fan comes on when triggered by the fan switch when it senses a pre-set temperature. For the Fiero, I think it's 210 or 215 degrees. This is reaching an overheating point, but isn't to the critical state, yet. The fan switch is the only sensor that has a sole purpose of controlling engine temperatures.
The AC circuit activates the cooling fan at any engine temperature, because of the extra load on the engine and because of the increased temperatures injected into the radiator intake air stream by the condenser that's placed in front of the radiator. The only way to check gauge operation without any tools is to turn off the climate control system, let the engine idle until you see the cooling fan come on. Knowing it should come on at just above 200 degrees, you can determine if it's correct by what your gauge indicates.
A simple non-invasive method is to obtain an infrared laser thermometer. Point the laser dot at the brass base of the gauge sending unit when the fan comes on and compare that to your gauge reading. Harbor Freight has them on sale at this very moment for $25.99. They have other uses like checking exhaust ports to see if each cylinder is burning equally, checking rotors for possible sticking or dragging calipers or for overheating bearings, etc.
Also, my 87GT gauge runs at about 150 with a 195 degree thermostat. Fan doesn't come on until it hits about 200-105.
The coolant fan comes on when triggered by the fan switch when it senses a pre-set temperature. For the Fiero, I think it's 210 or 215 degrees. This is reaching an overheating point, but isn't to the critical state, yet.
I have heard that the stock fan switch doesn't come on until it hits 235....and that there is a lower temp fan switch available at the 210 degree range you mention
[This message has been edited by 92wastheyear (edited 09-05-2013).]
I have heard that the stock fan switch doesn't come on until it hits 235....and that there is a lower temp fan switch available at the 210 degree range you mention
I wasn't sure what the standard temp was. Someone had recently said that 235 was very high for the fan to come on. Thanks for the link and correct info. I'd searched for the correct temp but couldn't find it on PFF.
A little over an hour ago, I installed my 180 and let the car idle until the cooling fan came on. On my gauge, it shows about 195, so it's possible that the engine may have a low temp switch installed. On a test drive, it did run slightly cooler than with the 195 thermostat.
I wasn't sure what the standard temp was. Someone had recently said that 235 was very high for the fan to come on. Thanks for the link and correct info. I'd searched for the correct temp but couldn't find it on PFF.
A little over an hour ago, I installed my 180 and let the car idle until the cooling fan came on. On my gauge, it shows about 195, so it's possible that the engine may have a low temp switch installed. On a test drive, it did run slightly cooler than with the 195 thermostat.
My commute this summer has routinely included a stretch of stop and go traffic that lasts about 20 mins or so. As long as I keep moving the car runs pretty cool and doesn't hit the 220 mark (according to my gauge). However in that stopped traffic, on the 80+ days, the temp will creep pretty quickly. I was turning on the AC in those situation and the temp would quickly come right back down. I am thinking of getting one of the fan switches from Rodney...probably the moderate one, and keeping the 195* thermostat. That looks like it would keep me from having to switch on the AC in those situations.
PS The only reason I was aware of the fan switch things is that I recently had it pointed to me
The only difference between the construction of a 185 degree thermostat and a 195 degree thermostat is the spring. The hole size is the same. That little disc that blocks the flow is the same. Everything is the same except for that spring. Once the engine is up to temp, they are both full open and the opening size is the same. The only difference is WHEN they start to open. Obviously the 185 will open before the 195. But once you're up to normal engine operating temp, they are both full open and have the same flow capacity. Take a 185 and a 195 drop them both in a cup of 200+ degree water and wait for them to open fully. Measure the opening and you'll find they are the same. Disc to seat, not hole diameter. Since the 2.8 in the Fiero is designed to operate above 200 degrees, all you will get with the 185 is a thermostat that is opening a few degrees sooner. You won't change the final operating temp. So if it was overheating with a 195 thermostat, it will also overheat with a 185. Here is something else I would do since you say the temp gage reads around 195 under normal conditions. Take the temp gage sensor with the wires still connected and drop it in a cup of boiling water (just the sensor, not the wires too) and look at the gage. If it doesn't read right at 212, or REALLY close to that, then you know how far off your gage is. That could be a bad sensor but I'd bet on the gage being off. The way to change the operating temp is to change the cooling system somehow. The easiest way to do that is to increase the amount of air passing through the radiator. More/bigger openings to allow air to enter and exit. Turning the fan on earlier than normal. Manually control when the fan runs. The easiest of all those is changing when the fan runs. Either by installing a lower temp fan switch or with a switch inside that I control. To recap, installing a 185 thermostat won't change the normal operating coolant temp. It will only change when the thermostat starts to open.
The only difference between the construction of a 185 degree thermostat and a 195 degree thermostat is the spring. The hole size is the same. That little disc that blocks the flow is the same. Everything is the same except for that spring. Once the engine is up to temp, they are both full open and the opening size is the same. The only difference is WHEN they start to open. Obviously the 185 will open before the 195. But once you're up to normal engine operating temp, they are both full open and have the same flow capacity. Take a 185 and a 195 drop them both in a cup of 200+ degree water and wait for them to open fully. Measure the opening and you'll find they are the same. Disc to seat, not hole diameter. Since the 2.8 in the Fiero is designed to operate above 200 degrees, all you will get with the 185 is a thermostat that is opening a few degrees sooner. You won't change the final operating temp. So if it was overheating with a 195 thermostat, it will also overheat with a 185. Here is something else I would do since you say the temp gage reads around 195 under normal conditions. Take the temp gage sensor with the wires still connected and drop it in a cup of boiling water (just the sensor, not the wires too) and look at the gage. If it doesn't read right at 212, or REALLY close to that, then you know how far off your gage is. That could be a bad sensor but I'd bet on the gage being off. The way to change the operating temp is to change the cooling system somehow. The easiest way to do that is to increase the amount of air passing through the radiator. More/bigger openings to allow air to enter and exit. Turning the fan on earlier than normal. Manually control when the fan runs. The easiest of all those is changing when the fan runs. Either by installing a lower temp fan switch or with a switch inside that I control. To recap, installing a 185 thermostat won't change the normal operating coolant temp. It will only change when the thermostat starts to open.
Yeah this is what I was getting at in one of my comments earlier in the thread. Just for clarification sake, I assume you mean that you need more air passing over the radiator rather than through the radiator. Air inside the cooling system is bad, of course
Oh dear, seems to be lots of opinions on this topic....
Reason I asked is because, my engine temp while driving never went above the 1/4 mark. ususally stayed around the 1st or 2nd line BEFORE the /4 mark. I just rebuilt the car, and its the same engine, but now the gauge is all over the place, from 1/4 to 1/2 to 3/4 while sitting. then zooom back down to 1/4...
This could be your temperature gauge sending unit going south on you.
They are pricey, and inconsistent.
I use a digital meat thermometer to check against my cab readings. I can tell you that in my case, the dash temp gauge is about 40* out. I know this because my rad fan switch is a 180* and the meat thermometer agrees with it. At the same time the dash is reading 220*.
Best to test with an independent gauge on an old system.
Temperature swings could also mean air pockets in the coolant system. There are several threads on PFF about burping the coolant system. You could also look in the Ogre's cave. I'm sure he has something on the subject too. If the system is properly filled and burped, then there are other problems that need to be looked at. But burped the coolant first. Sometimes it takes more than once to get all the air out.
