Does the thermostat fail gradually?

[melsas]

My temp gauge wil max about 2/3, almost 3/4. Never has gone past the halfway mark the last two summers. The fans run almost all the time. I replaced temp sending sensor 4-5 months ago because the fans run so much. Did not change fan operation.
Does the thermostat fail gradually resulting in progressively higher temps? Also, idle has gotten a little
rough.

[JSRS6]

Have you done either the 35k or 75k maintenance?

[LIRS6]

My temp gauge wil max about 2/3, almost 3/4. Never has gone past the halfway mark the last two summers. The fans run almost all the time. I replaced temp sending sensor 4-5 months ago because the fans run so much. Did not change fan operation.
Does the thermostat fail gradually resulting in progressively higher temps? Also, idle has gotten a little
rough.

My symptoms exactly; it was the thermostat. Expensive endeavour, which is probably why JSRS6 was asking u about 35k/75k services...my timing was good, as O2 sensors were being replaced under warranty,

[skribe]

Wow, I would stop driving the car until you resolve this. You are playing with fire (literally I guess.)
There are so, so many expensive failures on your horizon if you run this car hot... not something I would postpone, particularly with summer approaching.

[melsas]

35K was done at around 27K. I'm at 46K now. What temp reading is considered 'hot'? Anything over mid-point on the gauge?
Can you take the temperature with VAG-com? New user of VAG, so no experience.

[JSRS6]

Yeah, I had never seen mine go above halfway until the accident when my radiator started leaking. Even up to 165, and long periods of WOT. Good advice here, stop driving it. Get that fixed asap. Good luck.

[LIRS6]

35K was done at around 27K. I'm at 46K now. What temp reading is considered 'hot'? Anything over mid-point on the gauge?
Can you take the temperature with VAG-com? New user of VAG, so no experience.

Further to my earlier, and reflecting on skribe's comment, I too would have it attended to asap - my fans were running, the temp gauge was hovering at 5/8 for about a week, then the temp started spiking, which really got me concerned .. I parked it until I could get it to the dealer.

[hahnmgh63]

Yes you can take the temp through Vagcom. It is really only the accurate way to get a temp as for one the Gauge is not marked, and two, the gauge has what Audi calls a temp smoothing which means as you climb hills (or load up the engine) the temps increase some and going real easy the temps decrease but it will normally always display the halfway mark. With Vagcom I have seen over a 5'C temp difference from load to easy driving with no movement of the gauge. The senders are notoriously bad and should be replaced, especially if it is black plastic in color, the newer version is green and fairly cheap $25.

[JRS-RS6]

Given that your fans run excessively and you replaced the temp gauge 4-5 months ago without any change I would say there is reason to be concerned. Dealers (or at least not mine) do not change the water pump or thermostat on the 35K timing belt interval. Check with VAG-COM ASAP and than take corrective action before you have bigger problems on your hands.

[4everRS]

I for one believe that the T-stat can fail slowly. I have stated this on a few threads thus far. Mine did the same thing your is now doing, minus the high temp readings. My fans were on emergency mode and running from the moment I turned the key on, to 3 minutes after I shut the engine off. Sounds like a turbine.

Most t-stats in cars have a "fail-safe" feature. That is, if they fail (or start to) they fail in the open position. My water temp was consistently too low and the fans were running, hmmm, weird. I also got a CEL a couple times for the cooling system.

Based on info provided, it sounds like yours could be slowly failing (the bad way. aka t-stat NOT opening) sending your fans into emergency mode. Sorry

To look on the bright side, as least you'll be able to see if the timing belt in still properly tensioned.

[DHall1]

To answer your question.

Yes

I assume we are talking about a C5 RS6. right? Didnt we go thru this last year?

Was the thermostat replaced when the timing belt was done at 27K?




My temp gauge wil max about 2/3, almost 3/4. Never has gone past the halfway mark the last two summers. The fans run almost all the time. I replaced temp sending sensor 4-5 months ago because the fans run so much. Did not change fan operation.
Does the thermostat fail gradually resulting in progressively higher temps? Also, idle has gotten a little
rough.

[melsas]

C5 RS6.
The t-stat was not replaced at 35K service per lookup by local dealer. Previous owner in another state had it at that time.
I have contacted local dealer service rep about current issue. I am waiting on his response.
Thanks for all the input so far.

[DHall1]

Not anyone at fault for not changing the tstat at 35k.

Not the smartest move but no fault.

Sounds like your on the hook.


C5 RS6.
The t-stat was not replaced at 35K service per lookup by local dealer. Previous owner in another state had it at that time.
I have contacted local dealer service rep about current issue. I am waiting on his response.
Thanks for all the input so far.

[melsas]

If it's the t-stat, I'm letting Mr. Fidelity Platinum be on the hook for this one.

[DHall1]

Pay for a new timing belt and pass side roller if they go in for the tstat. Then your set for 35k.


If it's the t-stat, I'm letting Mr. Fidelity Platinum be on the hook for this one.

[GEN XER]

If it's the t-stat, I'm letting Mr. Fidelity Platinum be on the hook for this one.

LOL! Good luck with that.

[melsas]

Per dealer, the thermostat is sticking. Fidelity will pay total to replace less $100 deductible. Service Rep tried to up sell for timing belt, water pump,rollers,etc but I declined.
"Only" an additional $1,900 since 9 hours labor is covered. I'm 20K miles away from next timing belt (at 66K - 35K service was done at 26K). I only drive it 5-6K per year. One more year on service contract. I'll roll the dice this time. Out of curiousity,I did ask for price to extend svc contract.

[4everRS]

1900 !! That is total BS.

I would ask how many hours it takes to do the job once they already have it opened up. I would be surprise if a seasoned tech would take more than an hour to do it if they are already there. Then again, If that's the crap they will try to pull, maybe you don't want them doing the work.

Per dealer, the thermostat is sticking. Fidelity will pay total to replace less $100 deductible. Service Rep tried to up sell for timing belt, water pump,rollers,etc but I declined.
"Only" an additional $1,900 since 9 hours labor is covered. I'm 20K miles away from next timing belt (at 66K - 35K service was done at 26K). I only drive it 5-6K per year. One more year on service contract. I'll roll the dice this time. Out of curiousity,I did ask for price to extend svc contract.

[melsas]

New thermostat is installed. Temp gauge stays at 12 o'clock position.Oil temp seems lower, too. Fans run when A/C is on, but so, far fans have not run after
engine is shut down.
After shutdown hood feels warm but not hot. However, hood feels progressively hotter for two + hours after shutdown.

[DHall1]

As I noted above. At your mileage...you only needed the timing belt and pass side upper roller. 200 bucks in parts and maybe 1 extra hr in labor.

IMHO a bad move not to replace those two items. But that water is under the bridge and down the river at this point.




Per dealer, the thermostat is sticking. Fidelity will pay total to replace less $100 deductible. Service Rep tried to up sell for timing belt, water pump,rollers,etc but I declined.
"Only" an additional $1,900 since 9 hours labor is covered. I'm 20K miles away from next timing belt (at 66K - 35K service was done at 26K). I only drive it 5-6K per year. One more year on service contract. I'll roll the dice this time. Out of curiousity,I did ask for price to extend svc contract.