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Failed Thermostat Housing/Coolant Loss Info Gathering

ReadTheBook

Drag Race Newbie
Location
Bay Area Smoke Hell
Ride
2017 GTI Sport DSG
Edit 12/6/2019: Please file a complaint with the NHTSA for this issue using the following link, this would initiate the process for a recall.

Edit 2/3/2020: Please see post #153 for answers to a few questions one user had.

Edit 2/10/2020: Please see post #193 for another potential relevant cause of coolant loss

Edit 2/21/2020: As of now VW are still handing out revision M thermostat housings, per the repair on my wife's 2015 Golf SE. My 2017 Sport got the same part in April 2019.


For those interested, a thread has been started on the r/GolfGTI subreddit on Reddit.com asking for info about when your thermostat housing failed.

https://www.reddit.com/r/GolfGTI/comments/drna5m
Thought I'd put it here if folks want to contribute since so many of us have had this issue.

If you are not a Reddit user and wish to add your info, post it here I am happy to add it to the post for you. It would be tagged with your forum username and a link to your post here.
 
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avenali312

Drag Race Newbie
Location
Smyrna, GA
Ride
2015 VW GTI
Not a Reddit user, so here you go.

2015 Volkswagen GTI DSG (non-PP)

Replaced by dealer under powertrain warranty on September 5, 2019 at 38,700 miles.

I have no idea if it was just the thermostat though. They didn't tell me the specific culprit. They replaced the water pump, aux water pump, and thermostat all at the same time.

Edit: Adding photo from work order.

 
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Carlosfandang0

Drag Race Newbie
Location
UK
Ride
2016 3Dr GTi DSG CSG
Not on reddit either,

2016 Golf GTi DSG, non P/P,

Replaced under VW Das Welt used approved warranty on 10/07/2019 at 39,205miles,

Paperwork states ‘remove and replace thermostat housing’

Water pump was not replaced but after inspection I’m pretty sure the actual thermostat is also new, although parts used are not stated on the invoice,

The leak was very minor but there none the less.
 

ReadTheBook

Drag Race Newbie
Location
Bay Area Smoke Hell
Ride
2017 GTI Sport DSG
Not on reddit either,

2016 Golf GTi DSG, non P/P,

Replaced under VW Das Welt used approved warranty on 10/07/2019 at 39,205miles,

Paperwork states ‘remove and replace thermostat housing’

Water pump was not replaced but after inspection I’m pretty sure the actual thermostat is also new, although parts used are not stated on the invoice,

The leak was very minor but there none the less.
Not a Reddit user, so here you go.

2015 Volkswagen GTI DSG (non-PP)

Replaced by dealer under powertrain warranty on September 5, 2019 at 38,700 miles.

I have no idea if it was just the thermostat though. They didn't tell me the specific culprit. They replaced the water pump, aux water pump, and thermostat all at the same time.
Thanks guys. I've added your info.
 

JerseyDrew77

Drag Racing Champion
Location
Virginia & NC
Also not a Reddit user...

2016 GTI S 6MT

The housing failed at 61,200 and brought the issue to VWoA because the dealership refused to replace it WHILE I had warranty. In the end, VWoA covered the repair.
 

Jacobmk7

Ready to race!
Location
NC
Ride
2015 GTI S 4dr DSG
2015 GTI 63k, at 45k brought it in to get it pressure tested and it passed twice. Vw refuses to cover it under warranty because it passed even though you could visually see dried coolant dripping down the block. Service advisor said “I gotta be honest with you man, it kinda looks like mud to me”, what a load of bs. Didn’t pursue any future action because the tech who did the pressure tests goes to my church and my uncle personally knows him.:rolleyes: I top up the coolant every oil change at 5k, no biggie.
 

ChronicSPD

Ready to race!
Location
Imperial MO
Mine has been slowly leaking since around 10k, it's at 28k now and I've topped off the coolant 3 times. I'll take it in soon, but it's hard since I'm the only person that has worked on (or driven) the car since it was bought new.
 

ReadTheBook

Drag Race Newbie
Location
Bay Area Smoke Hell
Ride
2017 GTI Sport DSG
Didn’t pursue any future action because the tech who did the pressure tests goes to my church and my uncle personally knows him.:rolleyes:
No offense, but wtf does that have to do with anything? Who gives a F who knows who, you have a warranty and were denied for no reason on a well known issue that I've been directly told by my dealership is an acknowledged poorly made part from a shitty manufacturer. I'd have been livid. At the very least you should get your uncle to get that tech to do you a favor.
 

ReadTheBook

Drag Race Newbie
Location
Bay Area Smoke Hell
Ride
2017 GTI Sport DSG
Mine has been slowly leaking since around 10k, it's at 28k now and I've topped off the coolant 3 times. I'll take it in soon, but it's hard since I'm the only person that has worked on (or driven) the car since it was bought new.
Yeah, that's more or less how mine went. I first noticed it was low at 5k when I did my first oil change. I ended up topping up every 3–5 months until it was worked on at ~25k.
 

Jacobmk7

Ready to race!
Location
NC
Ride
2015 GTI S 4dr DSG
No offense, but wtf does that have to do with anything? Who gives a F who knows who, you have a warranty and were denied for no reason on a well known issue that I've been directly told by my dealership is an acknowledged poorly made part from a shitty manufacturer. I'd have been livid. At the very least you should get your uncle to get that tech to do you a favor.
Good point, but to me it’s not worth the hassle. Even if didn’t know the tech or anything, I would still have to jump through a bunch of hoops. It will most likely start leaking again in like 15k anyway, lol.
 

russiankid

Go Kart Champion
Location
PA
My 2016 GTI S and my wifes 2015 Jetta SE both have had slight coolant loss/smell. Both were brought to dealer around 35k miles, pressure tested and found no issue. Coolant continues to slowly disappear.
 

JerseyDrew77

Drag Racing Champion
Location
Virginia & NC
Looks like I'll be replacing the water pump soon because I have a small coolant leak again. As I stated above, the dealership only replaced the housing and not the pump.
 

aaronc7

Go Kart Newbie
Location
Clovis, NM
2017 Audi S3, 41k miles. Coolant will randomly drop a little low one day, and then be fine for weeks/months. One day there was a small puddle under the car in the garage. Seems to randomly leak vs slowly constantly over time.

Continuing to monitor for now. I have warranty left and open recall that needs done, but I've been putting it off since dealer is far away (passenger seat airbag switch recall).
 

ReadTheBook

Drag Race Newbie
Location
Bay Area Smoke Hell
Ride
2017 GTI Sport DSG
2017 Audi S3, 41k miles. Coolant will randomly drop a little low one day, and then be fine for weeks/months. One day there was a small puddle under the car in the garage. Seems to randomly leak vs slowly constantly over time.

Continuing to monitor for now. I have warranty left and open recall that needs done, but I've been putting it off since dealer is far away (passenger seat airbag switch recall).
FYI, document what you find, when you find it, with photos so you can show your dealer.
 

avenali312

Drag Race Newbie
Location
Smyrna, GA
Ride
2015 VW GTI
FYI, document what you find, when you find it, with photos so you can show your dealer.
This. Even though my photos I took were a couple of months apart, it clearly showed a 2" drop in coolant in the bubble under the hood. Even without the drip trail, I think they could have seen a lot just by that.

For example, I showed these that were taken a little less than 2 months apart...



 
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ThatWhiteRabbit

Passed Driver's Ed
Location
Lisle IL
Will post on reddit later. This is something I'm following in my own car closely.

For reference, 2017 S, 6MT, currently 32k miles, first noticed a faint coolant smell at about 10k miles. I kept an eye on the coolant and noticed it dropped abruptly my first summer with the car. Had a pressure test done, dealership said it passed and topped the coolant off. The level has remained steady since but I still smell coolant once in a while, under certain conditions.

An indy shop changes my oil/does routine maintenance and they're aware of the issue and are keeping an eye on the thermostat housing--they haven't seen anything yet.
 

Carlosfandang0

Drag Race Newbie
Location
UK
Ride
2016 3Dr GTi DSG CSG
Mine also passed pressure tests at two different dealerships, after the second time I returned with photos of the dried coolant around the housing (taken from underneath with belly pan removed) and they then replaced it without question!
 

RichardCranium

Ready to race!
Location
Arizona
My 2016 GTI S and my wifes 2015 Jetta SE both have had slight coolant loss/smell. Both were brought to dealer around 35k miles, pressure tested and found no issue. Coolant continues to slowly disappear.
Same story with my 2017 S. I've had to top it off twice now and it probably needs it again at 40k miles. They pressure tested it and said nothing was wrong, yet it's clearly losing coolant.
 
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