Hey everyone,

I just bought a 2001 Audi A6 2.7T not too long ago and loving the car so far! One issue I've run into is this.

After a cold start and driving the car for around 5 minutes, the temp gauge starts creeping slowly to the right toward the hot side. It will do this for about 5 minutes until it nearly reaches the farthest point of the hot side. Of course, I turn the car off before this happens.

After this, I check under the hood and it looks likes the coolant hasn't moved from the reservoir at all; it lays perfectly between the min and max lines. When I turn the car off, the fans go wild and loud for a good 10 minutes in some cases.

The car will do this consistently so it's not erratic behavior from the temp sensor, it's consistently headed toward the hot side. I'm still getting hot air through the fans. Before I take it to the shop, I want to get your thoughts about whether this is a coolant sensor issue or a thermostat, or something else. Thanks for any advice.

 

How many miles? When was the last time the thermostat changed? If you know.
Coolant sensor is cheap and easy to change. If it hasn't been change I would do it anyways. May or May not fix the prob.
you say both condenser and auxiliary fans are working properly?
Also possibly air in the coolant lines. Take the cap off the coolant reservoir run the car till it heats up, see if you can get it to burp.

 

Thanks for your response Philip. Our friend who is the previous owner said the timing belt was changed supposedly at 80 or 90k. I'm not sure if the thermostat was changed too. Are there tutorials for changing the thermostat? I've never worked on audis before. I know that the driver's side fan is working. How do I check on the condenser fan? Thanks!

 

Hi
I have 98 A6. The coolant temp gauge does not move above cold. And car make less heat inside.
Is this the thermostat, I got an estimate from a audi shop to replace it and thet want $400.
I live in Minnesota and it is very cold here. Is it all right to drive the car with a bad thermostat. Is it advisable to take it in the highway. Are there any other side effects other than no heat.
Thanks!

 

or is this simthing else other than the thermostat

 

To anyone who is confused on if its the CTS or thermostat, change the CTS first. It is a $30 dollar part and very easily DIY-able.

If the problem still exists, change the thermostat. While you are in there, it may be wise to change the timing belt and waterpump, and all the parts associated with the timing belt.

 

So is it safe to drive the car with what seems to be a stuck open tstat?

 

$30 if you get it from the dealer. I always use the coolant sensors from advance auto parts and they last a long time and work just as an OEM one would and they are $9 at advance And yes it is very easy to change.

You can drive a car with a thermostat that is stuck open. A thermostat that is stuck open will cause the car to take a long time to reach full operating temperature or not reach it at all. Driving like this though is 100% safe and ok to do. You might not have heat though depending on how stuck open the thermostat is.