Heat Problem For Audi 80 1.9tdi 1992

[A6_25TDI]

Welcome to the club...

I have the same problem. Mine stays at 78. I have written several posts about this, and the other problems that I have, but no answer yet. I am still trying to find out what's causing this. It's not normal, the engine is "happy" at 90 degrees. That's the optimum temperature. Neither 80, nor 100 are good.

Anyway, try to drive the car harder, see if you can get to 90. If you drive too smooth, that might cause the temperature to not reach 90. And I've read somewhere that a diesel engine that is left idling will never reach 90.

[Limbo]

When I drive the card harder, I reach 90 (hopefully it wont go above 95 anymore )

But it seems to have a preference for about 80, as it gets up to 80 and then hangs until I push it somewhat hard.

When I reach 90, and then go back to some slow city-driving, it tends to go towards 80 again.

Please post here if you ever find the answer to the question

[A6_25TDI]

How exactly do you drive it? What do you mean by "hard" and "slow"? Interested in speed, gears, rpms at which you change, rpms at constant speed, etc...

[Limbo]

First I want to say that I was for a long drive yesterday, in a place where the temp. usually gets up to about 95 - 100, I got 85 yesterday. I don't understand the huge difference, because the fans shouldn't start before it reaches 95. I'm guessing it has something to do with a delay in temp. shown inside the car and the actual temp. Any thoughts?

The car doesn't show rpms. It has a huge clock instead

When I refer to slow driving it is in the city, where I have to stop frequently for red lights etc., and I drive about 50 kmph in 3rd gear or 60 kmpt in 4th gear, depending on if it's downhill or not.

When I go out of town, I usually drive 80 - 90 kmph in 5th gear.

Overall yesterday the temp. was between 80 and 85.

[A6_25TDI]

Originally posted by Limbo@Oct 17 2005, 03:13 PM
First I want to say that I was for a long drive yesterday, in a place where the temp. usually gets up to about 95 - 100, I got 85 yesterday. I don't understand the huge difference, because the fans shouldn't start before it reaches 95. I'm guessing it has something to do with a delay in temp. shown inside the car and the actual temp. Any thoughts?
The car doesn't show rpms. It has a huge clock instead
When I refer to slow driving it is in the city, where I have to stop frequently for red lights etc., and I drive about 50 kmph in 3rd gear or 60 kmpt in 4th gear, depending on if it's downhill or not.
When I go out of town, I usually drive 80 - 90 kmph in 5th gear.
Overall yesterday the temp. was between 80 and 85.

Quoted post

I know that huge clock... had an 80 1.8S some time ago with no rpm gauge

1. The fans *must* start before 95, otherwise it's too late...
2. I don't think that there's any delay in showing the temp on the instrument cluster.
3. From what you're telling me, I'm convinced now that you have an underheating problem, though not that major (as mine is for example ). Try changing gears at a little higher rpm and maybe keep the 3rd even at 60kph (though this is not a solution...).

I'll keep you updated if I find anything about my problem.

[Limbo]

I HAD an underheating and an overheating problem

The overheating problem seems to be fixed until further notice, by changing the thermoswitch.

I wasn't even aware that I had an underheating problem until recently. When I bought the car, I remember the temp. staying constantly at 80. I just thought that was normal.

I will keep you updated if I come across any more info