possible time for a thermostat replacement??

[bakes]

For the past two days I've noticed that my temp dial is staying right on the C and not moving to half way between C and H. The problem is that it's not consistently staying on C. If I shut the car off for a minute or so and then restart it the temp needle will occasionally rise to the normal half way point.

I'm wondering if there is anything I can check first to see what the cause is? I've tried to search but not found anything conclusive. I've read some people say it could be an air pocket but I've not done any changes to the car for a long time so I'm not sure how an air pocket could be the symptom.

Is the replacement of the thermostat a tricky job? Does anyone know of the part number I'd need to order to replace it? Where approximately is this located?

Thanks for help or suggestions!

Greg

[mrdave]

Check out this thread: http://www.rs6.com/showthread.php/23644-After-run-fan-seems-possessed

It could either be the thermostat or a temp sensor.

The thermostat is not necessarily tricky to replace, but I would not recommend doing it without also doing a timing belt job since you have to take apart all of the timing stuff to get to the thermostat.

[lswing]

Any codes from a VCDS scan? ross-tech.com

[bakes]

Any codes from a VCDS scan? ross-tech.com

I'll try to run a scan tonight.

[P1054]

99% sure that's the temp sensor and not the thermostat. I had the exact same symptoms, the ~$15 coolant temp sensor fixed it for good. The sensor is on the back of the engine near the top, driver's side. Remove the airbox and you've got access. Be careful with the little plastic "C" clip that holds it in, if you drop it it's hard to get back. I tied a piece of thread on it just in case, and good thing as I dropped it once.

[RS Sick]

Exact same symptoms here last year and it was temp sensor. Tie some fishing line to c-clip so you can retrieve if dropped.

[Turbowned]

Run some tests, then start by replacing the temp sensor as it's cheap and easy. I replaced mine when my fans were running after the car shut off. It did the trick!

[bakes]

Update : replaced the temp sensor this am and it appears to have done the trick! First run after the replacement has seen the thermostat gage rise to the middle of C and H as expected.

I must say, I couldn't figure out how to disconnect the MAF sensors (I read I just have to squeeze and pull) as no matter what I tried I couldn't get them to separate. In the end I just used the tolerance of the wiring to just slide the air box back and work with the space it provided.

One question for those that have replaced the sensor. did you use a rubber o ring around the sensor part that goes into the coolant pipe? I ended up buying my sensor at a vw dealership and he thought I'd need one. When I took out the old one there wasn't an o ring and my attempt to use the one he provided resulted in a situation where I couldn't get the sensor to sit properly. In the end I didn't use it. Like those who commented, putting back in the retainer clip was a challenge but luckily I didn't drop it as I didn't tie any piece of fishing line to it or anything.

Thanks for all of the suggestions!

Greg

[RS Sick]

http://www.rs6.com/webkit-fake-url://05bd89d8-6912-49ca-90fa-77a77a7d9497/imagejpeg

[RS Sick]

You need the rubber o ring. Takes a little wiggling to get seated, then apply downward pressure while you slip the c clip into position. Not sure if the copied picture I inserted above worked; if not just google search rs6 coolant temperature sensor and it's one of the first few images that shows fitment of the o ring.

[RS Sick]

I'm thinking your old o ring must be stuck in the pipe otherwise i think you'd have a pretty pink puddle.

[bakes]

I double checked and confirmed the old o ring was in there...it was tough to get out. Put the new one in to make sure everything was new and fresh. No pink puddle!!!

[RS Sick]

Victory!