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Failed Thermostat Housing/Coolant Loss Info Gathering

geokilla

Go Kart Newbie
Location
Toronto, Ontario, Canada
Car(s)
2018 VW GTI DSG
The thermostat housing leak passes a pressure test. It leaks while the car is driven and the coolant is up to temperature. Tell them to visually inspect it. Every dealer is certainly aware of the thermostat housing leak and should know better than to pressure test it.
I'm beginning to think this is a common occurrence in VAG cars in general and the mechanics just accept it. The mechanic behind this YouTube channel works for Audi and every single Audi that rolls into the shop has low coolant. Until VAG redesigns their coolant and cooling system or an aftermarket upgrade comes along, this is something we'll have to live with for the rest of our ownership. Yeah if you go from max to min in 2000km, then that's an issue. But if it takes you 20k km, then it's probably considered acceptable.
 

jimlloyd40

Autocross Champion
Location
Phoenix
Car(s)
2018 SE DSG
I'm beginning to think this is a common occurrence in VAG cars in general and the mechanics just accept it. The mechanic behind this YouTube channel works for Audi and every single Audi that rolls into the shop has low coolant. Until VAG redesigns their coolant and cooling system or an aftermarket upgrade comes along, this is something we'll have to live with for the rest of our ownership. Yeah if you go from max to min in 2000km, then that's an issue. But if it takes you 20k km, then it's probably considered acceptable.
They don't have to redesign it just use a better thermostat housing.
 

dequardo

Drag Racing Champion
Location
America’s Dairyland
Car(s)
2019 GLI Autobahn
Same thing chief.
 

Royalion

Passed Driver's Ed
Location
SoCal
Our MK6 GTI would go thru water pumps under warranty. We changed it last time and has been trouble free.
I assume one issue was false torque because no previous tech chased the threads. The other is I believe the systems are commonly overfilled. Since keeping all our VWs is the the middle of the cross hatched area no issues.
 

Johaan

Passed Driver's Ed
Location
Atlanta
Saw this on my local group, class action suit over water pumps.

800 miles later, I still smell coolant after replacing everything. Leftover spill from the leak? who knows? It’s cooling better, but still kicks a stink when it gets hot.

I came really close to selling at Carvana, but held on. Figured I’d keep it till ready for a MK8.
 

jimlloyd40

Autocross Champion
Location
Phoenix
Car(s)
2018 SE DSG
Saw this on my local group, class action suit over water pumps.

800 miles later, I still smell coolant after replacing everything. Leftover spill from the leak? who knows? It’s cooling better, but still kicks a stink when it gets hot.

I came really close to selling at Carvana, but held on. Figured I’d keep it till ready for a MK8.
I'm not saying that you don't smell coolant but after they replaced my thermostat housing I swear I could smell coolant for a few months but it was fine.
 

Johaan

Passed Driver's Ed
Location
Atlanta
I'm not saying that you don't smell coolant but after they replaced my thermostat housing I swear I could smell coolant for a few months but it was fine.
I rinsed the skid-plate some time back and it improved, would have to remove it to do better. Seemed a lot of crap on it. I also had a radiator impact puncture in addition to the oil cooler and thermostat housing replacements—so it had to be leaking for a while from several spots.

I was riding with the windows open the other day and could smell it. It’s just annoying that it won’t burn off.

Were it my Jeep I’d just hose off the whole engine :p
 

jimlloyd40

Autocross Champion
Location
Phoenix
Car(s)
2018 SE DSG
I rinsed the skid-plate some time back and it improved, would have to remove it to do better. Seemed a lot of crap on it. I also had a radiator impact puncture in addition to the oil cooler and thermostat housing replacements—so it had to be leaking for a while from several spots.

I was riding with the windows open the other day and could smell it. It’s just annoying that it won’t burn off.

Were it my Jeep I’d just hose off the whole engine :p
As long as it's not still leaking the smell will wear off.
 

hoffnung

New member
Location
CA
Car(s)
'17 GTI Sport
Hi everyone, I posted a separate thread but wanted to add to this one as well. I had BFI Stage 1 dogbone insert earlier today. I took a turn spiritedly and heard a loud pop. I pulled off to the side of the road, shut off my engine, popped my hood and watched my coolant leak rapidly. Coolant tank is completely empty, left a trail streaming down the side of the road. I had it towed. Any idea of what exactly happened? I wonder if anyone has had a coolant line rupture from an insert?
 

shovelhd

Drag Racing Champion
Location
Western MA
Hi everyone, I posted a separate thread but wanted to add to this one as well. I had BFI Stage 1 dogbone insert earlier today. I took a turn spiritedly and heard a loud pop. I pulled off to the side of the road, shut off my engine, popped my hood and watched my coolant leak rapidly. Coolant tank is completely empty, left a trail streaming down the side of the road. I had it towed. Any idea of what exactly happened? I wonder if anyone has had a coolant line rupture from an insert?

My guess is that you didn't put the dogbone insert in with the vehicle flat. The bolt wasn't really engaged in the upper mount. The engine shifted under load and cracked the radiator.
 

hoffnung

New member
Location
CA
Car(s)
'17 GTI Sport
My guess is that you didn't put the dogbone insert in with the vehicle flat. The bolt wasn't really engaged in the upper mount. The engine shifted under load and cracked the radiator.
Interestingly, the car was on a lift when it was installed. I'm about to have it looked at by a shop but agree that's likely the case. Bolt threaded into lower mount giving the illusion it was threaded to upper mount thus resulting in excess engine movement causing something in the coolant system plumbing to crack.
 

Parabola

Go Kart Newbie
Location
Black hole sun
Car(s)
2015 GTI, 2016 GSW
Seems like every few yrs there is a class action lawsuit against VAG due to faulty water pumps. I don’t understand how the fuck have they not learned anything from numerous fiascos with water pumps in prior generations. Absolutely unacceptable.
 

jimlloyd40

Autocross Champion
Location
Phoenix
Car(s)
2018 SE DSG
Seems like every few yrs there is a class action lawsuit against VAG due to faulty water pumps. I don’t understand how the fuck have they not learned anything from numerous fiascos with water pumps in prior generations. Absolutely unacceptable.
That plus the thermostat housing leak. After all the years they have been producing the car it's unbelievable they can't fix it permanently.
 

hoffnung

New member
Location
CA
Car(s)
'17 GTI Sport
Seems like every few yrs there is a class action lawsuit against VAG due to faulty water pumps. I don’t understand how the fuck have they not learned anything from numerous fiascos with water pumps in prior generations. Absolutely unacceptable.
In my case, it was my fault or more specifically my shops fault for incorrectly installing my dogbone bolt which led to excess engine movement thus knocking out a coolant hose. With that said, I did note some coolant loss in the past and have had to add a couple of times.
 
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