Failed Thermostat Housing/Coolant Loss Info Gathering

[ReadTheBook]

Absolutely a known problem, in fact there should be a recall to check the condition.

Agree, but based on this thread, others on here, and the reddit thread, there are plenty of dealers to fail to catch the fact that these are obviously leaking.

 

[volks6]

Absolutely a known problem, in fact there should be a recall to check the condition.

There should just be a standing fix for free from VW on all 2.0T MK6 and MK7 water pump and thermostat housings. They all fail and will continue to fail.

 

[avenali312]

There should just be a standing fix for free from VW on all 2.0T MK6 and MK7 water pump and thermostat housings. They all fail and will continue to fail.

Yup, not sure how something like this exists across multiple generations. Too busy sidestepping diesel requirements, I guess.

 

[Carlosfandang0]

Oh damnit - I've had to top up my '17 twice now. I figured it was just evaporation and that the pressure cap doesn't seal perfectly, now I've got a new thing to worry about. It's even better because I just went out of warranty last weekend
Aside from the dropping coolant level what is the correct way to check for this leak myself? I have no residue on the oil pan (I was just under there changing the oil and noticed nothing). I read the reddit thread and did some light googling and didn't find any pictures of the weep hole / where to look.

**EDIT**
Researching some more this may be covered by the powertrain warranty, which I have for another 20,000km (I'm at 60,030 right now).

**EDIT 2**
I'm an idiot, in Canada the warranty is 80,000km everything, 100,000km powertrain so I'm definitely covered. Also, I have localized the leak to the upper passenger side of the radiator so I'll stop posting here because I don't seem to have this problem.

taken from underneath the car with the splash guard/under tray removed, the bottom of the picture is toward the front of the car, the circled area is the coolant deposits (which look a bit like limescale), when I showed this picture to the service manager at the dealership they booked it straight in for replacement even though it had passed two very recent pressure tests.

 

[zero10]

taken from underneath the car with the splash guard/under tray removed, the bottom of the picture is toward the front of the car, the circled area is the coolant deposits (which look a bit like limescale), when I showed this picture to the service manager at the dealership they booked it straight in for replacement even though it had passed two very recent pressure tests.

Thanks so much for posting that! I'll check my car just to be safe. Maybe I have 2 leaks!

 

[surfstar]

That's absolutely incredible since the powertrain requires coolant to operate and this is a very well known issue.

Did you speak to a regional rep or was it just the first line of CARE folks?

Just first line of CARE. They supposedly reviewed it with a supervisor or something. My certified mail paper letter with additional info was received 11/26 - we'll see how long before we get a response. I do plan on raising a stink, if needed. Its one thing to deny warranty coverage across the board, its very different to treat customers differently, arbitrarily.
Thanks for starting this thread, I had been meaning to search for info to fight the local dealer's denial, and the reddit was useful for submitting. Hope it works...

 

[Desslok]

Got my oil changed at @7k miles and it was already near the min coolant mark. The dealer topped it off and at 9.5k, it's back at the same level. I guess it's cheaper to replace thermostats and water pumps than to make ones that don't leak.

 

[anotero]

Quick remark: now that outside temperatures are dropping, our coolant levels will appear lower than before. "Duh," y'all will say. What I'm trying to say is that our levels now may not be as bad as we think. But still bad.

 

[dequardo]

Ambient temperature changes should have no effect on coolant level.

 

[anotero]

Ambient temperature changes should have no effect on coolant level.

They surely seemed to once temperatures dropped from 20ddgC to 5degC.

 

[Carlosfandang0]

They surely seemed to once temperatures dropped from 20ddgC to 5degC.

Ambient temps do not effect coolant levels.

 

[Winter]

Just had to have the thermostat housing replaced last week in my 2017 Golf at ~ 57,000 miles after the Low Coolant alert went early AM.

Went immediately to dealership by my office. The service rep/agent asked if they could do a pressure test as, duh, this shouldn’t be happening, especially given the fact I’ve come in two times prior needing coolant added and, plus, it was important to do before the 60,000 mile Powertrain warranty expired.
Of course, I agreed.

Pressure test failed, so they scheduled me to come back in when new parts arrived on Monday. Meanwhile, they added coolant and said I’d be fine in the interim, which I guess it was. Job didn’t take overly long and was all covered under warranty.

Per my receipt:

Technician verified Thermostat Housing leaking coolant. Replaced Thermostat, pressure tested, operating as designed.

• 1 THERMOSTAT (pt # 06L-121-111-M)
• 1 UNION (pt # 06L-121-131)
• 1 SEAL (pt # 06L-121-043-B)
• COOL .ADD. (G-013-A8J-1G)

FYI: The first time I had to have coolant added was at ~ 12,000 miles in July 2017. Then again in October 2018 at ~ 30,000 miles. Low coolant light/alert never activated these two times. I just kept an eye on the level under the hood.
I first noticed coolant level drop at around 6,000 miles.

Now I’m concerned I need the coolant housing replaced too....???
Apologies for an overly wordy/detailed post. Hope this helps someone.

 

[ReadTheBook]

• 1 THERMOSTAT (pt # 06L-121-111-M)
• 1 UNION (pt # 06L-121-131)
• 1 SEAL (pt # 06L-121-043-B)
• COOL .ADD. (G-013-A8J-1G

Now I’m concerned I need the coolant housing replaced too....???

leaks happen at the thermostat housing, which is what was replaced. you don't need a new coolant reservoir unless it is cracked somehow.

 

[Winter]

leaks happen at the thermostat housing, which is what was replaced. you don't need a new coolant reservoir unless it is cracked somehow.

Thank you! That’s what I’d assumed but wasn’t completely sure upon reading through the thread.

 

[ReadTheBook]

Anyone who is subscribed to this thread and has not already done so, please file a complaint with the NHTSA here:
https://www-odi.nhtsa.dot.gov/VehicleComplaint/?
This will help to initiate a recall or future service action from VW.