Thermostat Fail Signs...

[A4MZ]

Hey Everyone, I searched for a while and didn't see any pre-signs or symptoms of a failing thermostat so I wanted to see if anyone recalls what happened before it actually failed.

I have a 2013 S4 with 22,300 miles on it. It has the AWE Cool Front System and reservoir so I'm not sure if that would affect the systems.

A few weeks ago after starting the car, the "Low Coolant Warning" message popped up on the display. I added some coolant to the OEM and Aftermarket system and the light went off, no issues. This morning the warning message came up again. I popped the hood and checked the levels and both were fine. I drove the car for a bit and logged on VAGCOM to see if any issues would arise. By the time I got to work, the light turned itself off, the engine temp level did not move at all, and when I looked at the logging, everything looked okay.

Would you think this is a sensor starting to fail or a precursor to the thermostat crapping out?

Thanks in advance.

[CaptSlow]

I have yet to experience it, but if I recall from reading a thread here, Thermostat failing would increase your engine temp level and the car would tell you not to drive it

[xuandatou]

I have yet to experience it, but if I recall from reading a thread here, Thermostat failing would increase your engine temp level and the car would tell you not to drive it

A dealer in LA quoted my buddy $1200 to replace the thermostat for his 2013 S5 and claimed it would not be covered by warranty....which means $60 in parts, $1200 in labor, sounds insane to me..

[schirm]

I just had mine done. They day or two before I noticed my cooling fan still being on full blast after the car turned off. When running it sounded like it was going at 150%. You can just hear it being louder. 2nd day my temp gauge starting rising to high towed it to dealer. I had them do it for 1,065$. Went bad at 85,000 miles.

[CaptSlow]

A dealer in LA quoted my buddy $1200 to replace the thermostat for his 2013 S5 and claimed it would not be covered by warranty....which means $60 in parts, $1200 in labor, sounds insane to me..

Not covered under warranty? For a 2013? lolwut

[TAGHRP2]

A dealer in LA quoted my buddy $1200 to replace the thermostat for his 2013 S5 and claimed it would not be covered by warranty....which means $60 in parts, $1200 in labor, sounds insane to me..

Sounds very fishy, it should be covered by warranty "if the car still has warranty". I would rather go to a different dealer or call AOA and let them know the issue.

Yes!, sounded like thermostat issue only.


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[Joker S4]

Not covered under warranty? For a 2013? lolwut

That's what I was thinking. Why would that not be under warranty? I have a CPO 2012 and mine was replaced under warranty at around 40k miles. Overheated, loud, and warning came on that said to check coolant levels and not drive.

[A4MZ]

I just had mine done. They day or two before I noticed my cooling fan still being on full blast after the car turned off. When running it sounded like it was going at 150%. You can just hear it being louder. 2nd day my temp gauge starting rising to high towed it to dealer. I had them do it for 1,065$. Went bad at 85,000 miles.

Okay, sounds like my issue may be un-related to the T-stat then. I'm wondering if a sensor is going bad, if that's the case...any one have experience with that?

[CaptSlow]

Maybe it's water pump?

Or I just don't know what I'm talking about.

[kr3w45]

Okay, sounds like my issue may be un-related to the T-stat then. I'm wondering if a sensor is going bad, if that's the case...any one have experience with that?

If you are loosing coolant you have a leak somewhere. If the low coolant light came on but the coolant level was full then it may have been a sensor.

[A4MZ]

If you are loosing coolant you have a leak somewhere. If the low coolant light came on but the coolant level was full then it may have been a sensor.

I havent lost any coolant since I topped it off. I'll keep an eye on it and see if the light comes on again.

Thanks all!

[S4snowfan]

I just had mine done. They day or two before I noticed my cooling fan still being on full blast after the car turned off. When running it sounded like it was going at 150%. You can just hear it being louder. 2nd day my temp gauge starting rising to high towed it to dealer. I had them do it for 1,065$. Went bad at 85,000 miles.

This...

Mine went around 45k miles. My fan would blow well after the car shut off. Also you will get the Tep warning sign in your info screen area. And your thermostat will be off the chart. I drove mine for about a week before i got the parts to fix it as the dealer also quoted me $1,200... It is ridiculous because it took me 4 hours and i did not know what i was doing. An Audi Tech should be able to complete this job in 2 hours. even at $120 and hour and a $60 part i am not clear where they get $1,200.

[Triska]

Is thermostat still a ticking time bomb for B8.5 or just the B8s?

[wwhan]

At 34k miles, the only warning I got was temperature warning sign in your info screen area the temerature guage was at high. It said shut down now, but was in dense traffic no shoulder. Had to stop/start to get top a safe area, for flatbed.

[Johnnycash]

just replaced mine about 3 weeks ago. 2011, 53k

got raped by the dealership to the tune of 1k, put in a claim thru AOA which was promptly denied because they are c u n t s and reeling from the dieselgate scandal, only 3k and about 5months out of warranty on a known defective part...

symptoms are easy to spot fans will run on full blast all the time when car is on and after you turn it off.

if you are driving and worried about engine temps, you can turn the heat on highest temp and turn the fan to full blast and this should help you limp it home or to the shop etc

[ob_1jr]

Mine didn't fail fully, but got covered in the fuel rail recall. the dealer showed me my thermostat and said it was cracked and almost broke all the way. I was pretty close to having mine fail.

[613B6]

Mine failed 2 days ago 100K mark (MY2011), fans stayed on but hadn't overheated yet as I drove with the heater full blast. $700 CDN including the thermostat for the fix at my local German shop.

[kr3w45]

I replaced mine 2 weeks ago for 60 dollars haha.

https://www.ecstuning.com/Audi-B8_S4...All/ES2640066/

[S4'ed]

The only early warning you might get is the radiator fans running much more than before (as stated by other people in this thread),

OR, if you have a P3 gauge, you will see some above-normal coolant temperatures spikes shortly before the thermostat fails completely. The coolant temp gauge in the instrument cluster will not give you an early warning, as it is purposely inaccurate. It will only move above the normal middle mark when the thermostat has completely failed, and the engine is truly overheating.

[ENV²]

Fan stays on all the time and then pop goes the thermo.

[sacandagaD]

This...

An Audi Tech should be able to complete this job in 2 hours. even at $120 and hour and a $60 part i am not clear where they get $1,200.

Great question!

[shadycrew31]

I plan on doing my tstat when I clean the intake valves out, its been on my todo list for a while.

[ilovefood]

Try to bleed the coolant first, easiest step.

I replace the tstat myself last week. There was no sign indicates it's about to fail. When it fails you will hear loud fan noise, coolant temperature will go up, and coolant in the reservoir will remain cool.

[xuandatou]

I replaced mine 2 weeks ago for 60 dollars haha.

https://www.ecstuning.com/Audi-B8_S4...All/ES2640066/

It seems like this deal is a little bit better:
http://genuineaudiparts.com/parts/in...&siteid=214407

[A4MZ]

Try to bleed the coolant first, easiest step.

I replace the tstat myself last week. There was no sign indicates it's about to fail. When it fails you will hear loud fan noise, coolant temperature will go up, and coolant in the reservoir will remain cool.

Any tips on how to bleed the coolant?

[ilovefood]

1, Run car to operating temperature
2, remove top black cover on supercharger, you will see two black plastic bolts on each side underneath it.
3, Loose (DON'T REMOVE!) one of the bolts, then throttle the car to 2000rpm until coolant comes out.
4, Tighten the bolt and do the same to the other bolt.
5, Remove rain tray cover, you will see two pipes will the positive terminal box (iirc) in the middle. Pull the passenger side pipe until coolant flows out of the little hole on the pipe, this also needs 2000rpm.

That way you can force the air out of the coolant system.

[S4'ed]

Any tips on how to bleed the coolant?

Use a vacuum coolant refill tool, about $60 on Ebay. That is how the factory fills the system.

[ilovefood]

Use a vacuum coolant refill tool, about $60 on Ebay. That is how the factory fills the system.

This too, I was just too cheap.

[Vogz]

Bump for a great thread. Noticed my fans on constantly today. Checked coolant temp on P3 gauge and it was over 220F in normal driving. Ordered new OEM thermostat from Amazon tonight and it will be here tomorrow. Guess I'm driving the Turbo to work ;)

[Phoang1988]

Just had my thermostat and water pump replaced under CPO warranty today.

Took the car in last week and complained of low coolant level - I had figured I shouldn't really be needing to add coolant since this is a closed system. They pressure checked the system and found a leak where the pump was so they replaced that. They checked the car again and found the thermostat was not opening correctly and so that got replaced too. Car has 41k miles on it.

So if anyone is still under warranty, CPO or original, and has low coolant levels, just have it checked by the dealer - might have issues with the pump and thermostat like I did!

[rockstar143]

Did some part number checks and it looks like the B8 and B8.5 share the same Thermostat Part number so if it prone to failure that affects both.
Water pumps are different so that's probably the polymer vs aluminum pump difference. I would say using logic that if you have a B8 you should
change both if you have the SC off and if you're B8.5 you can get away with just the thermostat.

J.

[SSSSS5]

Did some part number checks and it looks like the B8 and B8.5 share the same Thermostat Part number so if it prone to failure that affects both.
Water pumps are different so that's probably the polymer vs aluminum pump difference. I would say using logic that if you have a B8 you should
change both if you have the SC off and if you're B8.5 you can get away with just the thermostat.

J.

I have B8.5 with polymer water pump fins, just put a metal one in because why not. Also note that Audi has multiple part numbers for these thermostats. I believe they have 4 revisions so just make sure you get the most recent one. ShopDAP or ECS will always sell you the most recent one.