Howdy folks, first time poster long time reader.
I bought my 96 2.5TL a little over a month ago with 100k miles and in seemingly perfect condition. I took it on my first trip down to San Diego this weekend from San Luis Obispo and on the way home I stopped in LA. When I started it back up again it started very rough and I noticed the temperature was pretty high. I popped the hood and the fan wasn't running but the coolant level was good. I decided to start moving again to get some air flowing and the temperature came right back down. The temperature came all the way back down to normal range and the car seemed to running absolutely fine. The check engine light was on and I know that the light stays on so I figured it was just the fan. I kept her up to speed all the way home and didn't slow down till San Luis Obispo. It started overheating again as soon as I slowed down. I got it home and let it cool down.
I start it up this morning and it was running rough at first, give it some gas and it smooths out. I took it to a mechanic and it overheated right outside and I had to kill it and pull it in dead. It is there right now awaiting diagnostics. The mechanic checked the radiator and there was no coolant visible at the top of the radiator but the resevoir was full. What do you guys think it is? Head gasket? Waped head? pistons? melted valves?
I might do the work myself depending on what it is. I'll reply back here when I hear from the mechanic.

Thanks in advance,
John

 

you said its fine when you drive but when you slow down it heats up? see if the fan is working properly. its not the thermostat?

 

Right, the fan wasn't running so I have to fix that but the question is what damage did I do when it overheated? It was running rough when I started it up but then seemed to run fine after that.

 

OK, I talked to the mechanic. He says the fans are working fine and the check engine light says a misfire in cylinder #4. He says that right now there is no sign of a bad head gasket or anything like that but it is still possible if there is a very small leak or something like that. They are going to replace the spark plugs (because of misfire) and fill the radiator to the proper level.
He thinks I should drive it for a week or two after I get the radiator filled and the new spark splugs and then check the radiator level and see if i am losing any coolant.

What do you guys think? Does this sound like the right way to go?



Thanks,
John

 

probably no damage from overheating, if you did like you said, ran the engine to bring down the temp than you should be ok.

to check the fan, do this: disconnect the battery, then recconect it about 5 minutes later. Start your car up, and in park hold the RPM at 3000 until the fan cuts on. If it doesnt cut on in a few seconds then you may check a fuse or connecter, etc... probably electrical. If it does cut on than lower the RPMs and let it idle in park for about 5 minutes before cutting it off..,

Otherwise, check the thermostat (most likely culprit), and water pump/hoses/heater core/heater valve(if our cars have one)...

Engine light is strictly for your emissions

 

I would suggest a pressure test on the cooling system. This will identify a leak and hopefully show it's not the head gasket.

Frankly, I would suspect a head gasket w/ the CEL indicating missing. Water from a leaky head gasket will cause spark plug misses and set the CEL. A bad fan motor wouldn't set the CEL, unless it causes overheating.

I've had fans out before (Accord) and car would run all day at normal temp w/o overheating unless you stopped and idled w/ AC on.

A leaking head gasket can force exhaust gas into the coolant and force it into the overflow tank, hence full overflow tank. There is a chemical test on the coolant which will determine if exhaust gas is entering the coolant. I would also have this test performed.

good luck

 

Thanks for the info fellas, here's the latest.

The mechanic told me today that the pressure test and the chemical test on the coolant showed no signs of leakage so they went ahead and put in new spark plugs (misfire in #4 cylinder) and topped off the radiator. He said that it was all fixed and that was all it needed.... When I started it at the shop it was rough so I shut it off immediately so I could show the mechanic. When he started it up it wasn't bad and he thought everything was fine. He says that there is still a chance that there is a bad head gasket (or something else) but the leak is so small that nothing is showing up on the tests. He wants me to keep driving it for a week and keep an eye on the coolant level and if it starts going down then there is a problem.

What do you guys think? I know there is a problem and I don't want to risk destroying my engine by "seeing what happens." My TL started up perfectly/smoothly every single time before it overheated. Should I talk to another mechanic? Does anyone recommend a mechanic in San Luis Obispo, CA? Please help a very frustrated new TL owner.

Thank you very much.