I have a 1996 Audi A4, and it was running like a dream up until a few weeks ago. Under normal driving conditions, the temp gauge would be straight up in the middle of the gauge.

As of late, it goes to up to 3/4 to the max line, and if i dont turn the heater on full blast while driving, it will trigger the overheat dummy light to turn on.

After inspecting the engine while its running, it seems that the main fan was spinning a bit slow... slow enough to stop it with my hand, and the aux fan wasnt turning on at all, even at those high temps.

So i replaced the fan clutch, thinking it was causing the issue, but its still having the same problem. I tested the Aux fan by turning the AC on, and it does start the aux fan spinning.

One question i have is when should the Aux fan be turning on? I know its a 3 stage fan, and if i read correctly, the AC triggers it to go to stage 2. Should this fan be at stage 1 during normal driving? Because it is NOT turning on unless the AC is on.

Second thing is i thought it may have been the T-stat or water pump, but the upper radiator hose does get hot when the engine is on, and i can visably see coolent being pushed into the overflow tank (from what i gathered in searches, means t-stat and pump are still good). The only odd thing, is that the lower rad hose stays fairly cool at all times.

Is my issue with the radiator being clogged or bad flow through it? or is there somthing wrong with my Aux electric fan (also, the 40a fuse for the fan in the fuse box is still good)

Any help is appreciated! Thanks!

DJ

 

cheapest thing to try would be the coolant temp sensor. common to go out on our cars. i have no idea whether or not it would trigger your symptoms, but i would imagine so.

 

i am having the same issues as of right now also..went to go pick up an oil pan gasket, and on the way home it started to overheat. turn on the ac stayed 3/4 on the temp. slowly it started to go down. never happen before till now. so after this happen ran back to the parts store and ordered everything i could imagine for cooling..replacing the hoses,radiator,timing belt kit,waterpump and so on.i did this because im not sure if the previous owner replaced anything and the miles on the clock are at 168k.so i just bought all these parts just to make sure. wondering also before i start tearing apart what other options can there be.

 

Well, one thing i am specifically worried about is the Aux fan...

When should this electric fan (coded as the auxillary air blower in the fuse box panel legend(the only 40a fuse)) be on?

Under what conditions should it turn on?