joeyvaz

So I picked up a 2001 A4 1.8t this week. Car is running great, but one thing puzzling me is the temp gauge. It only comes up between 1/4 and less than the middle mark. This is happening even after the hour long drive after picking it up. I popped the hood after a long drive and the engine is warm, hoses seem to have pressure in them too.

Can the thermostat be stuck open?
Can the gauge be bad?
Is there a specific test I can perfom with my Vag Com?
Can I take an external temp reading with my hand held temp gun.

Thanks,
Joe

99a4turd

mine does the same thing i havenot checked into it yet but my coolong fan runs all the time when the heat is on when the heat is not on the fan does not run and it get up to normal temp?

dm.A4.B5

Its a probably a failing a thermostat. I have changed it on mine when it was doing the same thing. When was the last time the timing belt was replaced? Usually people will do the timing belt and thermostat at the same time.

joeyvaz

It happens even with the heat off. Funny thing is, when I turn off the car after a long drive and turn it back on a few minutes later, the temp rises. After having the car on for a few minutes, the temp gauge drops way down while driving.

Timing belt was done roughly 30k miles ago. So the thermostat can very well be on its way out. All symptoms point to that. I'm going to try and change it tomorrow and see what happens.

dm.A4.B5

Well the waterpump is inline of the timing belt so as the engine works harder you are pushing more coolant through the system. So with what you are saying that would make sense. But like I said I had the same issue, basically the coolant would never heat up fully especially when driving. I had to do the timing belt on my car so I did the thermostat while I was there.

joeyvaz

new thermostat did the trick. car not sits at dead center on the guage and the heat is much better too. thanks

RobQ

The thermostat shouldn't fail that soon.
How long (time) since it was changed?
Who did you get the part from?

joeyvaz

Timing belt was done 2-3 years ago. It was an oem thermostat. It was stuck open just a little by looking at it, but it was enough to keep the car from heating up completely. New one fixed it right up.

dm.A4.B5

Cheers!