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Failed Thermostat Housing/Coolant Loss Info Gathering

berfles

Passed Driver's Ed
Location
PA
Car(s)
'16 GTI PP, 94 RX-7
Looking to get mine in before the warranty expires. I can smell coolant after I drive it and I have to top off multiple times a year. Even people who get out of my car can smell it.
 

jimlloyd40

Autocross Champion
Location
Phoenix
Car(s)
2018 SE DSG
Looking to get mine in before the warranty expires. I can smell coolant after I drive it and I have to top off multiple times a year. Even people who get out of my car can smell it.
Definitely sounds like the thermostat housing.
 

relive

Passed Driver's Ed
Location
USA
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.
Dealership texted and said that the thermostat housing is completely dry, and that they took a photo which they will share when I pick up the car. Is this sufficient proof that the thermostat housing is fine? I have never smelled coolant like others have reported, and the amount of coolant loss is small compared to other people in this thread.
 

jimlloyd40

Autocross Champion
Location
Phoenix
Car(s)
2018 SE DSG
Dealership texted and said that the thermostat housing is completely dry, and that they took a photo which they will share when I pick up the car. Is this sufficient proof that the thermostat housing is fine? I have never smelled coolant like others have reported, and the amount of coolant loss is small compared to other people in this thread.
Sounds legit. How much coolant are you losing and in how many miles?
 

gixxerfool

Go Kart Newbie
Location
New Jersey
Car(s)
2016 Golf R
Dealership texted and said that the thermostat housing is completely dry, and that they took a photo which they will share when I pick up the car. Is this sufficient proof that the thermostat housing is fine? I have never smelled coolant like others have reported, and the amount of coolant loss is small compared to other people in this thread.
Seems like you may be ok. if you don’t smell coolant, then you’re likely not leaking any. Keep an eye on the level as you have been and enjoy the car.
 

relive

Passed Driver's Ed
Location
USA
Sounds legit. How much coolant are you losing and in how many miles?
Photo with level and miles was posted yesterday. About an inch or so after 5000 miles.
https://golfmk7.com/forums/index.ph...olant-loss-info-gathering.368847/post-7592995

Seems like you may be ok. if you don’t smell coolant, then you’re likely not leaking any. Keep an eye on the level as you have been and enjoy the car.
Thanks again, I appreciate the 2nd opinion!
 

Tacomonster

Ready to race!
Location
Colorado
Car(s)
Gti 2019
So my gti has only 3000miles on it and I have to top it off 3 times already. I am in a similar situation where I am unable to locate the leak. Do we know if the lates revision of the thermostat rev “M” has fixed the issue once any for all? Sorry if this was already asked but I couldn’t find a solid answer. I also read that new gti will need to be topped off more often but will leak less over time. I am debating if I should bring it in the dealership now or wait until it gets worse.
 

gixxerfool

Go Kart Newbie
Location
New Jersey
Car(s)
2016 Golf R
So my gti has only 3000miles on it and I have to top it off 3 times already. I am in a similar situation where I am unable to locate the leak. Do we know if the lates revision of the thermostat rev “M” has fixed the issue once any for all? Sorry if this was already asked but I couldn’t find a solid answer. I also read that new gti will need to be topped off more often but will leak less over time. I am debating if I should bring it in the dealership now or wait until it gets worse.
I have not heard one way or the other if the product has ultimately been fixed. A part number revision does not necessarily a part revision. Typically manufacturers will revise part numbers when they switch production vendors. It is easier to track batches if there is a larger issue.

If you have just topped it off I would take a picture and document date. Drive the car and when it is low again, then go to the dealer. Explain to them the situation, show them the picture, but don't top it off before you go. Not mileage you topped it off at as well. If nothing else, you start a paper trail. From there you have the option of continuing to monitor it yourself and refilling or returning to the dealer. Keep in mind, it will be about documenting your concerns, they may not find anything initially, but it is important to get it on file.
 

amsr

Ready to race!
Location
Michigan
I think some of the coolant is getting by the cap in some of these cars. It's unclear if it's the cap seal or the reservoir causing the issue. Mine had the thermostat fixed and it still goes down slowly. I smell coolant near the reservoir on occasion. I also sometimes see coolant crustiness in the channel next to the cap. It's not overheating...
 

theDoktor

Go Kart Newbie
Location
Buffalo, NY area
Car(s)
2017 GTI Sport
I think some of the coolant is getting by the cap in some of these cars. It's unclear if it's the cap seal or the reservoir causing the issue. Mine had the thermostat fixed and it still goes down slowly. I smell coolant near the reservoir on occasion. I also sometimes see coolant crustiness in the channel next to the cap. It's not overheating...
If you see any coolant crustiness around the cap, replace the cap. There should be no coolant smell- if you smell it, it's leaking. Sooner or later, it WILL overheat. Hello new head...
Assuming it has VW spec coolant in it, the coolant will have a reddish tint to it . Drops on the ground will be easy to spot.
 

AdamSheikh

Go Kart Newbie
Location
FLL
Car(s)
2015 GTI MK7
My stock water pump somehow lasted 95k miles. Got it replaced as a precaution (figure it was past due) and sure enough it was seeping coolant ever so slightly on the under side. Now at 105k miles, that new pump sprung a leak so I had to get it replaced again (under the 1 year parts warranty) a few days ago.

Here's hoping the third pump's the charm lol. Seriously mind boggling that VW still can't make a water pump right after all these years and failures.
 

russiankid

Drag Race Newbie
Location
PA
My LS waterpump lasted 216k before it started weeping and takes an hour to replace. I am dreading doing it on my MK7 and wife's 1.8T.
 

avenali312

Drag Racing Champion
Location
Mableton, GA
Car(s)
2015 VW GTI
If you have just topped it off I would take a picture and document date. Drive the car and when it is low again, then go to the dealer. Explain to them the situation, show them the picture, but don't top it off before you go. Note mileage you topped it off at as well.
This is exactly what I did. I didn't even have to explain to my dealer that I saw the trail of dried coolant down to the oil pan, they saw the photos, mileages, and dates and basically said "we've seen this before, we got you" and took care of everything (parts changed out listed here: Project Red XIII: avenali312's OEM+ GTI - Post #93).
 

gixxerfool

Go Kart Newbie
Location
New Jersey
Car(s)
2016 Golf R
This is exactly what I did. I didn't even have to explain to my dealer that I saw the trail of dried coolant down to the oil pan, they saw the photos, mileages, and dates and basically said "we've seen this before, we got you" and took care of everything (parts changed out listed here: Project Red XIII: avenali312's OEM+ GTI - Post #93).
Excellent! Glad to hear that some dealers step up. I keep hearing more and more of dealers shafting owners for no reason.
 

Ridebjj

Autocross Newbie
Location
lasVegas
My stock water pump somehow lasted 95k miles. Got it replaced as a precaution (figure it was past due) and sure enough it was seeping coolant ever so slightly on the under side. Now at 105k miles, that new pump sprung a leak so I had to get it replaced again (under the 1 year parts warranty) a few days ago.

Here's hoping the third pump's the charm lol. Seriously mind boggling that VW still can't make a water pump right after all these years and failures.
You should have left the first one alone maybe. They don't suddenly fail catastrophically as far as I know, so probably don't warrant preventative replacement like a cam belt or something.
 
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