So much hate towards temp gauge.

[vwlippy]

So, a few months ago temp gauge stopped working. I replaced coolant temp sensor first since it was cheap and easy to replace. No fixy.

Next, off to the dealer. I assumed they would replace the thermostat - based on what I've read on here. NOPE, they said my after run/secondary water pump failed. They replaced, car worked fine for 3+ months.

Yesterday, temp gauge dies. 24 hrs its working again.

Seriously... why would they design a temp gauge to stop working when something was wrong with the cooling system. Dumbest idea ever. Thats when you need the gauge the MOST!

[Rub-ISH]

did they change the thermostat? most likely that is still and issue if they didn't

[vwlippy]

No they didn't. It worked fine for 3 months after I got it back, but that has to be the problem now.

[Travis Grundke]

It's the thermostat. Add it to the list of items that are guaranteed to fail on this puppy. Based on the number of people with this issue I think it's time to start pushing Audi of America for a service campaign on this part.

[everfresh59]

Is this an easy replacement?

[MisterJJ]

Is this an easy replacement?

Hahahaha. It's an Audi.

[vwlippy]

Is this an easy replacement?

Not really. You have to remove the alternator to get to it. blah

[everfresh59]

Not really. You have to remove the alternator to get to it. blah

So it's the labor that rapes you in the end...

[Travis Grundke]

From the discussions I've been following the cost is between $400-$600.

[everfresh59]

From the discussions I've been following the cost is between $400-$600.

Probably safe to say that this should be swapped when doing timing belt replacement... which sucks, since I had mine done last year...

[rick89]

My temp gauge is acting funny as well. Somtimes it works and sometimes it does not.

[vwlippy]

Probably safe to say that this should be swapped when doing timing belt replacement

Sounds like a good idea.

[Travis Grundke]

Probably safe to say that this should be swapped when doing timing belt replacement... which sucks, since I had mine done last year...

You know, I'm coming up on the timing belt anyhow - that's a *great* idea.

[Rub-ISH]

not only does the alternator come out...but usually they will pull the intake manifold as well

[SilverSquirrel]

not only does the alternator come out...but usually they will pull the intake manifold as well

not too bad on the 3.2 engine. remove the airbox, (drain the coolant) disconnect some hoses and wires, and you can get to the tstat housing.

[everfresh59]

can this also be done if you decide to clean the intake valves?

[Spitzbergen]

My temp gauge just crapped out also... BUT I have a check engine light also. Since I don't have a Vag-com I can't check the code but I do have an Appt. with the dealer tomorrow. Hopefully I won't get raped.

[ma2kster]

I did the thermostat replacement myself (on the 2.0 BPY engine). A few things I would have done differently;

1) Remove both battery cables (negative first), your alternator connects directly to the battery. Use WD-40 to free the alternator bushings. I tried multiple hours refusing to use any chemicals on my alternator and the bushings are stuck to the extend that I guarantee you no human being is able to free them as described in the repair manual. Just a little bit is enough.
2) you will need to disconnect turbo air charge line; don't remain underneath it while disconnecting (unless you care for an oil-shower)
3) I used rhino ramps, getting underneath the car will be required.
4) some quick-disconnects are not that quick or simple; a second hand is helpful (he/she taps on them lightly while you are yanking the connection)

and good luck, I spent 7+ hours. If you know what you are doing and have all the tools (XZN bits will be required too) it should be a 2 hour job. Take your time filling and adding coolant; it is easy to create an air-lock situation and you may ruin the head gasket...

[ma2kster]

My temp gauge just crapped out also... BUT I have a check engine light also. Since I don't have a Vag-com I can't check the code but I do have an Appt. with the dealer tomorrow. Hopefully I won't get raped.

At the outset the bad thermostat causes Pending-DTCs, then (I assume with a preset number of unsatisfied ECT conditions) it becomes permanent, and CEL comes on. I have vag-com, and was able to diagnose in detail; the fact is even-though the ECT is 75- 80 degrees (read through the MVB using vag-com) the instrument cluster gauge would go straight down to Cold... I think this is designed intentionally to tell/show the driver that there is something wrong with the engine cooling. In short, the symptoms definitely sounds like the thermostat; I was given a quote of $530 in the Washington DC area. Then I did the job myself, was $35 + coolant and lots of shop towels realized... Furthermore it took me two weeks to find a shop to accept the recovered coolant. It is highly toxic and very bad for the environment, shouldn't be dumped anywhere (please). Autozone or Advanced Auto doesn't take it either...

[vwlippy]

I think this is designed intentionally to tell/show the driver that there is something wrong with the engine cooling.

Yeah, except this is when you need to be able to read the gauge the most!

[ma2kster]

Yeah, except this is when you need to be able to read the gauge the most!

I haven't experienced an overheat situation (thank God), and I'm assuming the gauge quits working and points towards the "Cold" limit when the thermostat is stuck open/or prematurely open. I agree with you that the gauge is most needed when the temperature is abnormal. Perhaps, it is an exaggerated display of the normal than cooler operating temperatures. I'm sure it doesn't work the same-way when you have an overheating engine. I think the ECU keeps count of time since engine start-up/warm-ups and if the ECT doesn't reach a target value within a preset time then you start getting these DTCs (first pending DTC). I remember seeing a reference to this somewhere on the VCDS screen.

[mike3141]

The thermostat may not be stuck open when the system kills the temp gauge. The ECU programming monitors the coolant temperature and will kill the gauge if the coolant doesn't follow the profile that the ECU expects based on external temp, revs, etc. What usually happens is that the thermostat weakens over time and may open too soon or too late. We're now seeing the results mostly on '06 models (my previous '06 included).

[Barn01]

I have the same issue. I will try a coolant swap with G12 first before going to the t-stat. Since usually you swap the coolant during a t-stat change I'm guessing that at least half of the reported temp gauge issues are actually coolant related and no t-stat.

Read the last few posts of this thread

http://forums.vwvortex.com/showthrea.....-HELP!/page2

[Ut-A3]

My 06 just started having this symptom as well!!!
84K on her so far.

[SilverSquirrel]

I have the same issue. I will try a coolant swap with G12 first before going to the t-stat. Since usually you swap the coolant during a t-stat change I'm guessing that at least half of the reported temp gauge issues are actually coolant related and no t-stat.

Read the last few posts of this thread

http://forums.vwvortex.com/showthrea.....-HELP!/page2

the last post is the only factual one... the nonsense about the coolant's physical properties have nothing to do with this issue.
you are wasting g12 without doing the thermostat.

replace thermostat.
fill with fresh g12 or better 50/50, and move along.

[vwlippy]

Back from the dealer. No surprise, thermostat was replaced.

Also, while it was there they replaced the PCV valve (which I had already replaced on my own last year) and the Intake Manifold Flap Actuator for free under warranty.

I think the PCV valve is a little different than the one I replaced. Maybe they updated the part again?

[Travis Grundke]

Back from the dealer. No surprise, thermostat was replaced.

Also, while it was there they replaced the PCV valve (which I had already replaced on my own last year) and the Intake Manifold Flap Actuator for free under warranty.

I think the PCV valve is a little different than the one I replaced. Maybe they updated the part again?

How much for the t-stat replacement?

[Spitzbergen]

Thermostat good, sensor bad. Along with an oil change cost me a little over $200.00. I also got a new crank case breather valve and intake flap motor replaced under warranty. Thank you Audi.

[Travis Grundke]

The dealership will always want to replace the sensor first - it will work for a week or so, then you'll be back to the same problem.

It's the thermostat, guaranteed.

This problem is affecting just about everyone that's creeping over the 75,000 mile mark.

[everfresh59]

isn't a t-stat like 40$...

[mike3141]

The trick is getting access to it.....

[vwlippy]

The trick is getting access to it.....

Exactly.
I think the part is listed for $47, plus charges for a seal and coolant. Expect to drop about $500. Thankfully I had a $50 off coupon I received in the mail.