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Failed Thermostat Housing/Coolant Loss Info Gathering

AtlantaDad

Drag Race Newbie
Location
Cumming, GA
Contact the good doctor when you need to. He's been booked up pretty consistently, so there is a wait time at this point haha.

Edit: If you don't know who that is, just search the ATL MK7 group and you'll find him, or PM me.
That's who I was thinking of. ? Quite the drive from Cumming, but probably worth it. Car is going in to Eurofed for DSG service on Monday and they'll do an inspection...so I'll know for sure what's up. ?
 

ReadTheBook

Autocross Newbie
Location
Bay Area Smoke Hell
Car(s)
DVP Spektrm, MK4 R32
aaaaannnnnnndddddd my Wife's 2015 is at it again. Sigh.


thermostat housing leak.JPG
 

amsr

Ready to race!
Location
Michigan
So my car was at "MAX" when they returned it to me with the new thermostat in July. Seemed to hold the level they filled it to at least initially. Its now halfway down to "MIN". Its been basically sitting since November, having been driven maybe 3 times. (I stopped driving for a couple months due to a sports injury). Is it possible for this to recur even without the car being driven? Or is it just lower because its winter? Seems like the level (parked/cold) should always be the same, right?
 

avenali312

Autocross Champion
Location
Mableton, GA
Car(s)
2015 GTI
So my car was at "MAX" when they returned it to me with the new thermostat in July. Seemed to hold the level they filled it to at least initially. Its now halfway down to "MIN". Its been basically sitting since November, having been driven maybe 3 times. (I stopped driving for a couple months due to a sports injury). Is it possible for this to recur even without the car being driven? Or is it just lower because its winter? Seems like the level (parked/cold) should always be the same, right?

Similar experience here, though I daily my car (well mostly, my wife and I split commuting responsibilities, so it's driven every other day). New water pumps and thermostat in September, level has dropped from Max to a little above Min since then.

My body paneling is dirty inside the engine bay, so I need to clean it to watch for the cap blowoff residue like @stuntnuts has referred to earlier in the thread.

I also need to get under the car to see if there's a drip trail like before. I never did confirm if the dealer cleaned up the drip trail from the first failure. I hope they did haha.
 

Boltsfan17

New member
Location
Tampa, FL
So to finally close the loop on my issue found in this tread: After the initial thermostat housing replacement (under warranty Part # 06L-121-111-M), the car dumped me less than 24 hours later due to the tech not properly bleeding the system allowing air in causing the sensor to assume there was no coolant. Towed back to dealer where system was purged and car returned to me. Two days later, I notice the temp would gradually climb to dangerous levels after just a few minutes of parked idling. Took it back and here's what they found per the work order notes:

"Verified customer complaint. Performed cooling system test and found leaking coolant at union/connector from oil cooler and thermostat housing. Found union/connector seal not properly sealing coolant in system. Removed all required to gain access to union. Removed union and replaced with new. Verified repair and performed cooling system pressure test and verified no leak."

Thought I'd share this last bit of info just in case anyone else has to deal with this. Checked my coolant level today and it's still right where they filled it after two weeks of every day driving. I will say my service advisor was super nice and had my wheels repainted at no cost.

Scheduled for a Unitronic Stage 1 tune Friday. Still have about 18K on powertrain warranty. After all that has happened, I may still chicken out and wait on the tune until after warranty is officially gone.
 

Parabola

Go Kart Champion
Location
Black hole sun
Car(s)
15 GTI, 22 Tiguan
This is why I hate dealerships touching anything on my car even if it’s warranty related...something always gets messed up and it ends up costing me time and aggravation.
 

ReadTheBook

Autocross Newbie
Location
Bay Area Smoke Hell
Car(s)
DVP Spektrm, MK4 R32
So to finally close the loop on my issue found in this tread: After the initial thermostat housing replacement (under warranty Part # 06L-121-111-M), the car dumped me less than 24 hours later due to the tech not properly bleeding the system allowing air in causing the sensor to assume there was no coolant. Towed back to dealer where system was purged and car returned to me. Two days later, I notice the temp would gradually climb to dangerous levels after just a few minutes of parked idling. Took it back and here's what they found per the work order notes:

"Verified customer complaint. Performed cooling system test and found leaking coolant at union/connector from oil cooler and thermostat housing. Found union/connector seal not properly sealing coolant in system. Removed all required to gain access to union. Removed union and replaced with new. Verified repair and performed cooling system pressure test and verified no leak."

Yeah so leaking at oil cooler. They didn't do the repair properly, at least that's what I was told in private after mine leaked at the oil cooler a couple months after my first repair.
 

avenali312

Autocross Champion
Location
Mableton, GA
Car(s)
2015 GTI
Also, interesting update on my wife's car for @stuntnuts, her April 2014 (early) build 2015 Golf SE Sport does not have that pressure release area you called out. Her tank and my tank on my 2017 are different. Zero evidence of anything coming out of her tank either.

Just to give some relative data on this since I was looking at mine last night, my 2015 GTI S (build date April or May of 2015, can't remember exactly) does have the item you're pointing to in the photo. It also has the silica bag in it.
 

Boltsfan17

New member
Location
Tampa, FL
Yeah so leaking at oil cooler. They didn't do the repair properly, at least that's what I was told in private after mine leaked at the oil cooler a couple months after my first repair.
My service advisor told me another shop foreman would be making the last repair. Could only assume the first one screwed up twice and wasn’t going to be given a third shot at it.
 

Wrath And Tears

Go Kart Champion
Location
Azusa, CA
Car(s)
17 Sport, 99 E36
Just dropped my car off at the dealer this morning for a coolant leak. When I had the car on a lift it seemed like it was the thermostat. I was kinda hoping they would have it done today as well, but it's been 6 hours and I haven't heard from the SA yet. Probably should have just done it myself on a day off, but oh well. Not sure how I'm getting to work tomorrow ha.
 

Wrath And Tears

Go Kart Champion
Location
Azusa, CA
Car(s)
17 Sport, 99 E36
I just realized they did have a place to request a rental. I was used to having my old dealership provide me a loaner. Good news is that they are finishing it up and I'll be able to pick it up in a little over an hour.
 

ReadTheBook

Autocross Newbie
Location
Bay Area Smoke Hell
Car(s)
DVP Spektrm, MK4 R32
I just realized they did have a place to request a rental. I was used to having my old dealership provide me a loaner. Good news is that they are finishing it up and I'll be able to pick it up in a little over an hour.

Please do make sure to log that NHTSA complaint buddy!

I dropped my wife's 2015 SE off this morning. It's 2.5 months out of warranty, but I have tracked the coolant loss and there is visible corrosion as I posted above, so I'm hopeful it will be covered since it's a highly known repeat issue. We'll see.

Edit 2/21/20: An update to post #227 and the above comment...
My wife's car was goodwill covered for the repair. They did the thermostat and water pump together.
Thermostat is -M revision (same as my 2017 Sport got back in April 2019), water pump is -C revision.


We were just 3.5 weeks outside the 1 year / 12k repeat repair coverage warranty and 2.5 months outside of the powertrain by time, but still under by miles. We have serviced that car at the dealership a few times, including customer pay 6AT service (non-DSG), and an alignment and we own multiple VWs.

When I spoke to him about continuing coverage for this issue, the Service Director stated that all of those things combined with the fact that the corrosion and leaking of that much fluid likely hadn't occurred within just the last 3 weeks, gained us near instant approval from VWoA for repeat repair coverage. Multiple cars, even some dealer service, and overall loyalty goes a long way, apparently.

He feels we will eventually see extended coverage for this issue, similar to the MK6.

Invoice of the work done:
IMG_7794.jpg
 
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