Failed Thermostat Housing/Coolant Loss Info Gathering

[RennWerks]

It bears repeating at p.19 of this thread that this problem -- i.e., coping with cheap, indifferently manufactured water pumps -- has been a "Volkswagen issue" for the last 45 years. And by no means is this unique to Volkswagens. BMW transformed it into an art form three decades ago when Fritz first turned to Wolfgang and said, "You know, we could make these things out of plastic." The past is prologue, gentlemen. The only thing that's changed in the past 45 years is how long it takes to replace one cheap, indifferently manufactured water pump with another of like kind and quality.

 

[avenali312]

Has anyone found a company anywhere in the world making aluminum housings yet?

Do we know this would fix the issue? Is the actual housing itself warping due to the plastic, or is it the seal? I'd think even if the housing was aluminum, you still have the chance of it leaking at the mating point. I apologize since I feel like we have talked about this before, but I didn't really get a good rundown from the dealer on why it failed, just that it was replaced for free haha.

 

[ReadTheBook]

For the MK6

https://www.uspmotorsports.com/06H-121-026-DD-USP-Cast-Aluminium-Water-Pump.html

They have this one for the MK7, but really just the same plastic housing with metal impeller

https://www.uspmotorsports.com/Ulti...w-Metal-Impeller-For-Gen-3-MK7-06L121111.html

So I guess the answer is no

Yeah and I don’t do business with USP any more. That’s a story for another post.

 

[ReadTheBook]

Do we know this would fix the issue? Is the actual housing itself warping due to the plastic, or is it the seal? I'd think even if the housing was aluminum, you still have the chance of it leaking at the mating point. I apologize since I feel like we have talked about this before, but I didn't really get a good rundown from the dealer on why it failed, just that it was replaced for free haha.

It was stated to me by the service advisor and a tech that the thermostat housing physically warps over time, nullifying the seal.
However, the seal itself is also vulnerable to oil leaking onto it in the event of a leaky oil seal and causing it to fail.

So yeah, I feel an aluminum housing could fix most of the problems for most people.

 

[amsr]

It bears repeating at p.19 of this thread that this problem -- i.e., coping with cheap, indifferently manufactured water pumps -- has been a "Volkswagen issue" for the last 45 years. And by no means is this unique to Volkswagens. BMW transformed it into an art form three decades ago when Fritz first turned to Wolfgang and said, "You know, we could make these things out of plastic." The past is prologue, gentlemen. The only thing that's changed in the past 45 years is how long it takes to replace one cheap, indifferently manufactured water pump with another of like kind and quality.

Yep, my previous car (a 2011 3 series) suffered the same issue. It was well known in BMW circles that their water pumps and thermostats would fail. Audi has the same issue with the A4. Prior to owning German cars, I’d never replaced a single cooling system component.

 

[Ridebjj]

^^^ I had an e46 3 series for a while and indeed had to replace thermostat and h20 pump. I remember it being a pretty easy job compared to what I've read on how to do it on the gti.

The e46 also had the failing expansion tank common problem. That also was an easy install.

 

[geokilla]

Got my car back. As usual, they did the pressure test and said there were no issues despite topping off 3 times at a dealer now.

 

[shovelhd]

You have to take off the belly pan and take a picture of the leak.

 

[ReadTheBook]

Got my car back. As usual, they did the pressure test and said there were no issues despite topping off 3 times at a dealer now.

Yeah pull the belly pan and spot it yourself. If it looks like they cleaned off corrosion, call them on their bullshit.

 

[jimlloyd40]

Got my car back. As usual, they did the pressure test and said there were no issues despite topping off 3 times at a dealer now.

The thermostat housing leak always passes a pressure test.

 

[stuntnuts]

Got my car back. As usual, they did the pressure test and said there were no issues despite topping off 3 times at a dealer now.

For the 4 millionth time.....when they "pressure test the system" MAKE them also pressure test the cap!!!

 

[geokilla]

For the 4 millionth time.....when they "pressure test the system" MAKE them also pressure test the cap!!!

I know but I can't make them, especially not with physically distancing around due to COVID. I even told them how it's most likely related to the thermostat housing.

 

[JC_451]

Is -knowing- the coolant is slowly leaking the problem, or is this causing actual problems with the car?

 

[geokilla]

Is -knowing- the coolant is slowly leaking the problem, or is this causing actual problems with the car?

Well twice it was below the minimum line so I imagine if I was tracking it, it's no good. Of course I should be checking my fluids before I go anyways. This time it was just above minimum so I reckon while acceptable, still no good.

 

[shovelhd]

A slow leak is a problem waiting to happen.