OK.....this isn't Fiero specific, per se, as it involves my Suzuki Swift, but I *have* seen a number of Fiero engines with this amount of carbon build up so I think it is valid.

I have an engine that appears as though the oil was never changed and the oil used was probably low quality. There is about a 3/8" layer (no exaggeration) of carbon build up on the head and inside the valve cover. I have heard that running a quart of transmission fluid in the oil will clean it all out eventually. Does this really work? Anyone have any other suggestions?

Just trying to get my winter beater running again. I bought this engine to replace mine after the woodruff key went south (and took the crank with it), but with my luck this other engine is almost as bad as mine!

Thanks.

Eww, never mix forgin materials with your oil, not only will it not get to the areas you want, you will subject your main bearings to inferior oiling.

A few tricks include a "seafoam" treatment, also known as "gm top end cleaner". Some people like to work small amounts of water, about a cup or so over the course of a few mins down the intake. Fancy fuel injector cleaners are fairly effective, but some seem to be better than others.

yuck. must have TONS of blow-by to crap it up so much. but, I'd say the Sea Faom appraoch is the way to go. it does attack the mess from many angles. just worried with that much crap coming loose, you may clog the oil return. thinking maybe a slow approach - like just using good premium detergent oils & changing weekly for a month.

Yeah.....it's pretty nasty. It is actually running a bit better since tuning it up and changing the oil, but still not 100%. I will just do weekly oil changes until it gets itself cleared out....well, that and I'll give the Seafoam a shot (can't hurt).


Thanks again.

Your talking about the build up of oil right? not carbon from unburned fuel INSIDE the head? all the seafoam in the world will not clean the crap on top of the head out!

Back in the draft tube days, kerosene was commonly used to clean engines. They just replaced the oil with kerosene and ran the engine for a few minutes. Likely ruined many engines that way but it did clean the internals.

diesel engine oils are supposed to be high detergent...but might take awhile to clean it up

I'd drain the oil out, replace it with 50% Dex (auto trans fluid) and 50% 10w30 and run it for 10 minutes. Its safe as long as you don't leave it in there and it gives the engine a nice cleaning. Transmission fluid is a high detergent oil, so should break the stuff down.

After that put some fresh oil in it and a fresh filter of course.

You could also run Diesel oil through it like suggested above.

quote Originally posted by spark1: Back in the draft tube days, kerosene was commonly used to clean engines. They just replaced the oil with kerosene and ran the engine for a few minutes. Likely ruined many engines that way but it did clean the internals.

I used to use kerosene too. works good. I would add a quart into the oil, let it run for a few minutes and drive it up the ramp & drain it out. worked great. but, one day, my oil pressure sending unit failed - well - started leaking right after I added the kerosene. was never sure if it was the kerosene that wrecked the sending unit - but never done it again since. use synth oil now, and have never had a sludgey motor again.

running anything but oil through your oil system, is asking for problems. It is not easy to completely empty the "contaminated" oil from your system by just draining it.

quote Originally posted by darkhorizon: running anything but oil through your oil system, is asking for problems. It is not easy to completely empty the "contaminated" oil from your system by just draining it.

normally, I agree, but in cases like this - there is already stuff other than oil that needs to go.

I dont know if this holds true today but; cars used for short rides like city some cars often have a more gum and carbon build up in them. For one thing they spend a lot time running cold which can mean a ri/ch A/F ratio. If thats the case then with you car, be careful as to how you clean it. Engines suffer more wear during starts especially cold starts than driving, whereas oil has to get to bearings with each start. I'd rather have a car 200K highway mile on it then one with 70K miles fo short trips. Back to the cleaning, if the car was a driven like city car 2 miles here, 3 miles there and park it and shut it down each time, then your bearings may have a lot of wear. If you clean those oil deposits up too good, it may make the gaps bigger and drop oil pressure. Some say with todays oil its not the case..........

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Ive slowly poured Coke down 4bbs to break it up. I dont know exactly how you would do that to a throttle body though. Maybe use a spray bottle and shoot it in directly in the throttle body WHILE YOU RUN THE ENGINE at a fast idle. I also clean out crankcase by substituting a quart of auto trans fluid for one quart of oil and change it again in a hundred miles or so. I have also done the fill it up with kerosene trick with no after effects. I just dont run it with the kerosene in it, just put a few gallons in and let it set overnite, drain it back out. I had one engine i pulled the plugs out and filled it with kerosene till it was full to the plugs....it was totally sludged up to where the oil came out like syrup. Guy hadnt changed oil in 10 years (really....he told me so).

http://www.cyclo.com/additives_oil_trans.asp

On a nasty engine I add it to the oil (all it contains is 30W oil and a really high does of oil detergents found in normal oil) and then change the oil in that car when it get's really dark. It seems to hit at 1000 miles. do that 2-3 times and you will clean out the gook safely. use really cheap oil and decent filters as you need to catch all the crud.

wouldent be a swift gt would it? i used to have one(acually ive owned 3 swifts/metros)... 8grand fury! fun car, anyway, if i were you i would remove the oil pan, clean it WELL, scrape off all of the penzoil sludge off of the crank caps, throughtly clean the oil pick up tube (brake part cleaner is your friend!!!), leave pan off,(with plastic pan under eng) move to the valve cover, remove it, use what ever you can you scrape off as much of that crap that you can, especially anything loose, and around ANY moving part, use trans fluid to wash away all that youve broken loose,, then spread a layer of motor oil on the rockers/follers/cam/lifters to wash away the 100% trans fluid, then get back under the car and wash away (with a spray lubricant wd40, PB, liquid wrench) all of the loose debris that flushed down from above, then reasemble everything, add fresh oil(no additves) run it at idle for 10 mins, then at 2,500 for 5 mins, change oil and filter again with a higher quility oil (not syn tho) and you will be good to go, if you just dump in a bottle of trans fluid, or seafoam... the eng is doomed for sure, do not do that! thats only for lightly dirtied engines, its NOT made for thick deosits., if you want a relable winter beater, this process should only take you 2 hours, and the car will be sound afterwards.,

MHO...

Thanks for the suggestions guys. Just to clarify things a bit....I recently bought this car from a junkyard, so I don't know it's history at all. All I do know is that the engine is coked up (yes, from burnt oil building up). I currently have 3 qts. of oil & 1 qt. of ATF in the crankcase.....I drove it to work last night and it is evident that this engine has more issues. It has absoutely no power and won't rev past 4500 RPM's or go faster than 50 MPH. I also put a little more than 3 gallons of gas in it before heading to work and I ran out on the way home (it's a 46 mile round trip, so about 13MPG?). There is something wrong somewhere, whether its a plugged cat or timing issues or just a tired broken engine. I'll have to figure out if it's worth the hassle trying to fix it or not.

I was going to suggest one of Ed Park's de-carbonizing kits, but your engine sounds like it may be too much for it.

yeeeeeahhh... if you decide that you wana get rid of it..... leeemmmee know!!!!, i have a dohc turbo intercooled 1.3 waiting to drop in a shell. hehe yall didnt hear that!, and yeah prolly cat/ might have sat in high water as far as you know., say if its not knocking or reving really slow (like its locked) then its prolly something simple., have any pics of the car? ricarrro seats? 5 speed? color?

quote Originally posted by 88 Silver Formula: yeeeeeahhh... if you decide that you wana get rid of it..... leeemmmee know!!!!, i have a dohc turbo intercooled 1.3 waiting to drop in a shell. hehe yall didnt hear that!, and yeah prolly cat/ might have sat in high water as far as you know., say if its not knocking or reving really slow (like its locked) then its prolly something simple., have any pics of the car? ricarrro seats? 5 speed? color?

No knocks or anything like that. It revs fine in neutral, but is completely gutless in gear. My '92 is a rust bucket, but the engine ran well until the crank key way distorted itself too far. It is half a step away from teh junkyard (after I strip the good stuff off of it).

The '91 has an almost flawless interior and is white with a 5-sp. It has the factory Recaro style seats and is mostly rust free (there are a few minor areas). he body is a bit banged up....I think most of that came from the junkyard. The front & rear fascias are torn up and there are some hail dings on the roof and the right rear quarter panel is pushed in a bit. It is a solid car though.....it just doesn't run very well. The bad news is that there is no title and I may or may not be able to come up with one.

I have a feeling it is the cat.....it looks original and the car has 169K miles, so it's probably due for a change. There is still the possibility that the crank key is starting to let go as well.

If all else fails, you can just give me that turbo engine!

Just an update......the cat was bad. I removed it and the insides were all broken up. I gutted it out and re-installed it and it now runs & drives! There are still problems to work out, but at least I can go faster than 50 MPH now!