GOLFMK8
GOLFMK7
GOLFMK6
GOLFMKV

Failed Thermostat Housing/Coolant Loss Info Gathering

seanmcd1

Drag Racing Champion
Location
SC
Just had this repair (leaking T-stat housing) for the second time, at 54K miles. First time was around 28K miles. I'm hoping it lasts a little longer this go-round as it most likely will be out of warranty by then...
 

ReadTheBook

Autocross Newbie
Location
Bay Area Smoke Hell
Car(s)
2019 AT, 2018 S4
Just had this repair (leaking T-stat housing) for the second time, at 54K miles. First time was around 28K miles. I'm hoping it lasts a little longer this go-round as it most likely will be out of warranty by then...
Given you have 1 year /12k miles repair warranty, I’d at least take a look at it from below shortly that time period is up and see if you see any evidence of dry coolant/corrosion, then you can just take it back in and have them redo it and keep kicking that can down the road.
 

Supermoto

Go Kart Newbie
Location
San Diego
Car(s)
GTI MK7 SE DSG
I have a 2015 GTI SE that I purchased CPO 4 years ago. I noticed coolant loss after 2 months of driving, took it to VW and they said nothing is wrong. Kept driving and before my warranty ended I took it back to VW for the same issue (had to top off every 4 months) and they said nothings leaking. Now I am out of a warranty and still loosing coolant, and I found the source when working under the car; the waterpump/thermo housing. What courses of action do I have out of warranty on a 6 year old car?
 

avenali312

Drag Racing Champion
Location
Mableton, GA
Car(s)
2015 VW GTI
I have a 2015 GTI SE that I purchased CPO 4 years ago. I noticed coolant loss after 2 months of driving, took it to VW and they said nothing is wrong. Kept driving and before my warranty ended I took it back to VW for the same issue (had to top off every 4 months) and they said nothings leaking. Now I am out of a warranty and still loosing coolant, and I found the source when working under the car; the waterpump/thermo housing. What courses of action do I have out of warranty on a 6 year old car?

Either try to fight the dealer that they were wrong (probably not going to work out), or buy replacement parts from FCP Euro with lifetime warranty and, if you don't want to tackle it yourself, find the cheapest labor Euro indie shop in your area you can that you trust.

FWIW, I have a 2015 as well and had it replaced once under powertrain warranty. The new one has been on there more than a year and 12k miles, so I'll be in the same boat as you if/when it fails again.
 

jimlloyd40

Autocross Champion
Location
Phoenix
Car(s)
2018 SE DSG
I have a 2015 GTI SE that I purchased CPO 4 years ago. I noticed coolant loss after 2 months of driving, took it to VW and they said nothing is wrong. Kept driving and before my warranty ended I took it back to VW for the same issue (had to top off every 4 months) and they said nothings leaking. Now I am out of a warranty and still loosing coolant, and I found the source when working under the car; the waterpump/thermo housing. What courses of action do I have out of warranty on a 6 year old car?
If you can't get the dealer to fix what they obviously missed and if you do it yourself get the parts from FCP Euro. If you can't do it yourself you should let them get the parts if they warranty their work. If you supply the parts and it leaks you will have to pay for labor again if you supply the parts.
 

gixxerfool

Go Kart Newbie
Location
New Jersey
Car(s)
2016 Golf R
I have a 2015 GTI SE that I purchased CPO 4 years ago. I noticed coolant loss after 2 months of driving, took it to VW and they said nothing is wrong. Kept driving and before my warranty ended I took it back to VW for the same issue (had to top off every 4 months) and they said nothings leaking. Now I am out of a warranty and still loosing coolant, and I found the source when working under the car; the waterpump/thermo housing. What courses of action do I have out of warranty on a 6 year old car?
I would fight that tooth and nail. If you still have copies of the documents showing you have asked them to check and they signed off there was no issue, I would go back and talk to the manager or director explain to them the situation. If they refuse to cover it under good will, I would just kick all the info to VWoA. It is a common issue and they know it.
 

seanmcd1

Drag Racing Champion
Location
SC
Given you have 1 year /12k miles repair warranty, I’d at least take a look at it from below shortly that time period is up and see if you see any evidence of dry coolant/corrosion, then you can just take it back in and have them redo it and keep kicking that can down the road.
So was studying my receipts - looks like in 2018 at 27K miles, they only replaced the water pump and seals. Thermostat housing is not listed. This time round (54,600 miles) they replaced Thermostat housing (06L121111M), Union (06L1211131) and gasket (06K121043B). I do remember having to top off the coolant after the first visit way sooner than expected, and eventually a few months before I took it in I was topping it off every few weeks and seeing small puddles on the garage floor. Hoping it lasts a good while now.
 

relive

Passed Driver's Ed
Location
USA
I am taking my car in for the last service before warranty expires. Is this amount of coolant loss normal? Seems normal to me, but want to get other opinions, in case the housing needs to be replaced soon.

1613937219306~2.jpg
 

gixxerfool

Go Kart Newbie
Location
New Jersey
Car(s)
2016 Golf R
I am taking my car in for the last service before warranty expires. Is this amount of coolant loss normal? Seems normal to me, but want to get other opinions, in case the housing needs to be replaced soon.

View attachment 203947
All things being equal, no amount of coolant loss is normal. It is a sealed system. If you're losing coolant somewhere. It could be burned off, it could be leaking out. I would certainly do a good visual from underneath before taking it in so you have an idea if there is an issue. If the dealer attempts to say it's fine, then you know already. As @jimlloyd40 asked, if the car was hot in the second picture, but cold in the first, then yes that is normal. You will get expansion as the car gets warm.
 

relive

Passed Driver's Ed
Location
USA
Was the engine temperature the same when you took each picture?
All things being equal, no amount of coolant loss is normal. It is a sealed system. If you're losing coolant somewhere. It could be burned off, it could be leaking out. I would certainly do a good visual from underneath before taking it in so you have an idea if there is an issue. If the dealer attempts to say it's fine, then you know already. As @jimlloyd40 asked, if the car was hot in the second picture, but cold in the first, then yes that is normal. You will get expansion as the car gets warm.
The car was sitting inside for at least 24 hours when each picture was taken, so the car was cold and the ambient temperature would be ±5°F. I will bring this up with the service advisor since there is coolant loss.

Edit: Any tips on what to say if they push back and say that it is normal and the level is still above the min line? I don't have an easy way to crawl under the car to do a visual.
 
Last edited:

gixxerfool

Go Kart Newbie
Location
New Jersey
Car(s)
2016 Golf R
The car was sitting inside for at least 24 hours when each picture was taken, so the car was cold and the ambient temperature would be ±5°F. I will bring this up with the service advisor since there is coolant loss.
I have read too many times how dealers try to push these off, for whatever reason. They will say they pressure tested and the leak that are common to these are not shown with a static pressure test. Good luck with it. When I found mine leaking, I was very specific to the advisor about what and where I found it. It makes it harder for them to blow it off.
 

jimlloyd40

Autocross Champion
Location
Phoenix
Car(s)
2018 SE DSG
I have read too many times how dealers try to push these off, for whatever reason. They will say they pressure tested and the leak that are common to these are not shown with a static pressure test. Good luck with it. When I found mine leaking, I was very specific to the advisor about what and where I found it. It makes it harder for them to blow it off.
You're exactly correct. They try to convince you that it passes a pressure test so it isn't leaking. It only leaks when you're driving and the engine is up to temperature. It's a pretty slow leak but if they visually inspect the thermostat housing there will be staining if it's leaking there.
 

relive

Passed Driver's Ed
Location
USA
I have read too many times how dealers try to push these off, for whatever reason. They will say they pressure tested and the leak that are common to these are not shown with a static pressure test. Good luck with it. When I found mine leaking, I was very specific to the advisor about what and where I found it. It makes it harder for them to blow it off.
You're exactly correct. They try to convince you that it passes a pressure test so it isn't leaking. It only leaks when you're driving and the engine is up to temperature. It's a pretty slow leak but if they visually inspect the thermostat housing there will be staining if it's leaking there.
Thank you both for your input. If they push back, I will ask them to provide me a picture of the thermostat housing to make sure that it is not leaking from there.
 

gixxerfool

Go Kart Newbie
Location
New Jersey
Car(s)
2016 Golf R
Edit: Any tips on what to say if they push back and say that it is normal and the level is still above the min line? I don't have an easy way to crawl under the car to do a visual.
You can sometimes see the leak from the top. The housing lies underneath the intake manifold next to the trans. The leak usually ends up crawling down the front of the block. It will build up on the pan rail. An inspection mirror will help if you can't get underneath. This is a known issue with these so arming yourself with info will help.
Ask them to see it from underneath if they're so sure its ok.
 
Top