Car overheating

My car keeps running hot/overheating. The exhaust smells like pancake syrup. The coolant is constantly getting low. We have to add coolant about every month or two. There is not a visible leak. It’s not dripping anywhere where we can see. Our mechanic, and best friend, is an awesome mechanic and can fix almost anything, but my car has him stumped. He’s tested the radiator, the head gaskets, the fans, replaced the thermostat, etc. He’s tested everything and can’t find the problem. It’s happened 4 times in the last 6 months. It’s usually just while it’s idling and goes back down as soon as I start driving, but this last time it did it while I was driving. I’m just wondering if anyone has any insight or has had this problem.


If you have to regularly add coolant, and there is no visible leak, then there may be a bad head gasket, as an example

May we assume your mechanic put the car on a hoist and pressurized the coolant system?

As far as that test fluid goes, I’ve seen examples where it stays blue, but you’ve still got a bad head gasket, cracked block, head, etc.

Did he put in a thermostat of the correct temperature rating?

for what it’s worth, I’ve run into new aftermarket thermostats which actually CAUSE overheating, because they’re defective, right out of the box

Has he tested and/or replaced the coolant pressure cap?

What kind of vehicle is this, anyways?

1909 Huppmobiles will do that.
Seriously, we could help you far more if we know what you were driving. Year, make, model, mileage, stuff like that.

There are two sides to keeping an engine cool. One is cooling the coolant. The other is not generating excess heat. If he can’t find the problem in the cooling system, perhaps the engine is generating too much heat. Improper valve timing, a restriction in the exhaust (often when there is one it’s in the catalytic converter. They contain ceramic honeycombs that can be fractured and crumble), improper spark timing, these are all common causes of overheating.

If he’s truly checked and/or replaced everything in the cooling system, he might want to start looking at things that can cause overheating.

I have to admit, however, that your symptom sounds like a classic cooing system problem.
When the engine is hot, is the fan running?
Did there used to be a fan shroud that’s no longer there?
Did he thermally “map” the radiator to ensure that it’s dissipating heat evenly and sufficiently?
Is the radiator free to pass air? Is the AC “radiator” (called a “condenser”) freely passing air?

One BIGGIE: does your Huppmobile have the engine radiator and the transmission cooler in the same unit, like Fords do? If so, did your mechanic check to see if there’s mixing of the fluids?
Are you losing tranny fluid?

I urge you to feel free to show this to your mechanic. Perhaps there’s something in here that he’s overlooked. Even the best in the world overlook things on occasion.

Post back with the answers. We do care.

I think he checked the cap and changed a leaky gasket. Sorry! It’s a 2008 Saturn Outlook with 72,000 miles on it. He said he did a full radiator check/ran all the tests. He said the fan is running properly. I’m not sure if tranny fluid is low. Neither my mechanic or the people that change my oil (they check all your fluids and top them off) have ever said it was low.

The exhaust smells like pancake syrup.

This statement alone would make me check and check and check again for a head gasket failure.

Nice catch ASE.
OP, do you know how he checked the head gasket?