Another Overheating Thread....
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From: Beaverton, OR
Another Overheating Thread....
Hey folks been a long time since I been here but I know this is the place to go for those nagging problems that seem to stump me.
Quick refresher... car is a 1990 80 FWD w/ 2.0L and 5 speed tranny.
So on to the problem. about a month ago it started having overheating problems, but only when in heavy traffic...
One symptom is driving when at highway speeds or when it is cold the engine doesn't come up to normal operating temperature, only up to the first mark on the temperature gauge.
The overheating predominantly happens in the afternoon/evenings when stuck in rush hour traffic. At these times when not moving the temp beging to quickly rise to the mid point and above on the temp gauge and then at the high point the low coolant light begins to flash.
I have checked for leaks and found the return from the heater core to the engine block was loose at the engine end and has been tightened so see no more problem here, no weird odors, no white smoke out of the tailpipe and the radiator fan is working.
Any ideas folks?
Quick refresher... car is a 1990 80 FWD w/ 2.0L and 5 speed tranny.
So on to the problem. about a month ago it started having overheating problems, but only when in heavy traffic...
One symptom is driving when at highway speeds or when it is cold the engine doesn't come up to normal operating temperature, only up to the first mark on the temperature gauge.
The overheating predominantly happens in the afternoon/evenings when stuck in rush hour traffic. At these times when not moving the temp beging to quickly rise to the mid point and above on the temp gauge and then at the high point the low coolant light begins to flash.
I have checked for leaks and found the return from the heater core to the engine block was loose at the engine end and has been tightened so see no more problem here, no weird odors, no white smoke out of the tailpipe and the radiator fan is working.
Any ideas folks?
AudiWorld Junior Member
Joined: Sep 2012
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My guess is that you have two problems. The cold running is likely due to a faulty thermostat. The overheating is likely due to a cooling fan not kicking in. The latter could be caused by a relay, sensor, or the fan motor itself. Good luck.
Thread Starter
AudiWorld Member
Joined: Apr 2009
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From: Beaverton, OR
I wondered about the thermostat but because of the multiple problems wasn't sure.
I know the motor for the fan is ok because I can turn on the A/C and the fans kick on as they should.
I know the motor for the fan is ok because I can turn on the A/C and the fans kick on as they should.
AudiWorld Junior Member
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If the fan is working properly when the engine gets hot, then your problem may be as simple as a thermostat stuck in a partially open position. Too much coolant flow when the engine is cold. Not enough coolant flow when the engine gets hot.
Thread Starter
AudiWorld Member
Joined: Apr 2009
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From: Beaverton, OR
Could it be that simple? Kind of makes sense as I can turn on the A/C in the afternoons to force the fan to come on but the engine still overheats. While in the morning if I let the car idle for any length of time the temp begins to rise but as soon as I'm on the highway the temp goes way down. I'll have to baby it this week and tear into it this next weekend.
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From: Washington
uhhhh Just because the fan comes on with the a/c doesnt mean its coming on with the radiator thermo fan switch. Two totally different control systems operate that. Its obviously your problem, fans not running at high temps. Probably just the switch on the bottom of the radiator for the fans, or wiring for it has corroded.
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You have a bit of junk stuck in your thermostat opening, which has caused the thermostat to jam. You're EXTREMELY lucky that it did this partially open, instead of all the way closed.
But since the stat likely can't open all the way either, you're going to have major issues if you don't swap it out soon.
The fan can run all it wants, but if the coolant isn't flowing, it isn't doing its job.
But since the stat likely can't open all the way either, you're going to have major issues if you don't swap it out soon.
The fan can run all it wants, but if the coolant isn't flowing, it isn't doing its job.
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Thread Starter
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From: Beaverton, OR
Well, replaced the thermostat and temp sensor... seems to have fixed most of the problems...
still not sure what's going on with the fan... it seems to come on sometimes... like after a 15 minute test drive and then idling in the driveway...
But not other times... like the next day when I put in heavy freeway traffic and the engine promptly overheated again and the fan did not come on.
I can get to and from work with little problem and the engine temp is now running in the propper operating range, except during the aforementioned traffic jam...
But the newest problem is that heater hose from the heater core to the cylinder head looks to have a crack at the block end and is leaking small amounts of coolant... but probably getting worse by the day... and to make matters worse those hoses seem to made of unobtainium according to my local German auto / Audi parts source...
Is this one of those cases when you replace one thing it makes the next weekest link in line fail, and so on, and so on, and so on...
still not sure what's going on with the fan... it seems to come on sometimes... like after a 15 minute test drive and then idling in the driveway...
But not other times... like the next day when I put in heavy freeway traffic and the engine promptly overheated again and the fan did not come on.
I can get to and from work with little problem and the engine temp is now running in the propper operating range, except during the aforementioned traffic jam...
But the newest problem is that heater hose from the heater core to the cylinder head looks to have a crack at the block end and is leaking small amounts of coolant... but probably getting worse by the day... and to make matters worse those hoses seem to made of unobtainium according to my local German auto / Audi parts source...
Is this one of those cases when you replace one thing it makes the next weekest link in line fail, and so on, and so on, and so on...
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