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View Full Version : Overcooling - Thermostat or Fan fault?



pologt
14-01-2008, 10:31 PM
Hi, I hope you can help. Just purchased 1.8se and trying to iron out a few teething problems!

When driving, the car hardly heats up at all (temp gauge about 65), same with oil temp. The gauge is ok as it goes up a bit if the car idles for a while.

I reckon the thermostat is stuck open but I'm not sure how the viscous fan is meant to operate. It runs all the time. Most viscous fans I've seen on other cars do this but the Haynes manual seems to suggest it shouldn't turn at all until about 80 degrees???

(The electric fan does not run all the time.)

Thanks in advance for any advice, Ian

passat>sport
14-01-2008, 10:41 PM
the Haynes manual seems to suggest it shouldn't turn at all until about 80 degrees???

The viscous always spins! You are correct about 80 degrees, This is when the viscous internals tighten up to make it spin more faster.

What do your heaters blow like?

pologt
14-01-2008, 10:56 PM
It's hard to tell with the heater as the climate control works its wonders but I must say the 'blast' from the vents isn't the warmest I've ever had in a car.

Heat comes out reasonably quickly from cold though.

If the fan is operating correctly then, I think it must be the thermostat. That's ok... cheaper than a fan I imagine.

Many thanks, Ian

passat>sport
14-01-2008, 11:02 PM
Heat comes out reasonably quickly from cold though.

MMMM, Thermostat sounds ok to me.

Maybe your heater matrix is a little clogged and not letting the correct heat off!

pologt
14-01-2008, 11:11 PM
I'd say the heating is adequate but not brilliant.The main symptom though is the engine being too cold. I think if the matrix was blocked it would make it hotter not cooler???

passat>sport
14-01-2008, 11:26 PM
I think if the matrix was blocked it would make it hotter not cooler???

What I mean is when the antifeeze and like is not changed when it should be. It leaves a coating on the matrix (not blocked in a sense) but stops the matrix from letting the correct heat off.

This is a well known fault in which folk have had there matrix changed. on all cars, not just yours!

pologt
14-01-2008, 11:35 PM
Thanks for your help. I'll change the thermostat and flush the cooling system.

passat>sport
14-01-2008, 11:36 PM
Yes change the thermostat, I wasn't thinking on the last comment. :o

pologt
13-02-2008, 12:18 AM
Hi, just a quick update incase anyone else is experiencing a similar problem.

I finally got round to changing the thermostat and my temp gauge reaches the centre fairly quickly now.

It's worth trying if you have similar problems, it only cost about £12 from Audi (remember to get a new rubber seal).

Good luck!

rhencullen1989
13-02-2008, 01:12 PM
Just a note to add, i also had same problems with the temp gauge not working, mine was also the thermostat (£5 from AVS) your car should have the pink/red G12+ coolant, don't ever mix this with other coolants as it will react and ruin your cooling/engine. The idea of the G12+ is that it is long life and hence should never need changing, except where the coolant has been topped up with water and diluted the ratio. I would not expect a heater matrix to block up under normal circumstances.

pg20
13-02-2008, 11:10 PM
Hi, I'm having the same problem with my temp gauge. Can anybody tell me where the thermstat is located ? (1.8 se Avant) :1zhelp:

pologt
14-02-2008, 12:46 PM
That's the same model as mine. You need to remove the engine undertray and tackle it from below... I used ramps.

It is near the front on the left (nearside).

The bolts are a little tricky... I needed a really slim socket for one and had to loosen some kind of stabiliser bar that was in the way of the other.

Use some grease on the new rubber seal to hold it in place when you are replacing the thermostat cover.

When refilling the anti-freeze, half pull off the rubber heater hose (near bulkhead) until the small hole in the tube is past the stub. This allows the air to bleed out of the heater matrix. (Remember to push it back on when done!)

Good luck.