QuestionQUESTION: Hey Todd.
My 2002 GP 3.8 N/A has a brown, grease-like goo at the top of the radiator neck and on the bottom of the rad cap.
It's quite thick and it keeps building up every 4 to 6 weeks.
I can't figure out if it's engine oil or trans fluid.
Is there any history of this with the N/A 3.8?
What is your best guess as to what this is and where it's coming from?
Thanks
ANSWER: Hi colin:
a few things it could be #1 that car had a recall on it at one time where we added a stop leak agent to the cooling system. That could be it. it could be tranmission fluid or the car is old enough that the rubber hoses in the cooling system are breaking down. when the engine is cold grab on to the hoses if the feel spongy that me the the root cause. when it's hot check the tranmission fluid level and top off if need be an keep an eye on it. Engine oil leaking into the cooling system doesn't happen on that engine.
Good luck :-)
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QUESTION: Thanks Todd.
All coolant hoses have been replaced and/or inspected recently.
I suppose the trans cooler could be leaking, but I haven't noticed any significant ATF loss.
Would the lower intake gasket allow oil to seep into the cooling system?
While there is no measureable loss of coolant, the brown, sticky goo sure looks like engine oil.
AnswerNO if the intake was leaking ti would leak coolant into the engine oil not the other way around. You can try flushing the cooling system with prestone chemical flush it's a dry 2 part flusher just make sure you follow the directions on the can to the "T" and make sure you do an extra clean water flush after that stuff is nasty and if you don't get it all out it starts to eat away at metal and gaskets. Was this thing ever down on coolant meaning a coolant leak? if so ait trapped in a dexcool engine that has a lot of mix metal parts meaning aluminum and cast iron that is a chemical reaction that takes place and it starts to oxidise the coolant and it sludge looks like rust. that could be your issue also???
