MK7 TDI Thermostat Housing

[CodyR]

Hello All,

I have got my 2nd coolant leak in the last month and I believe its the thermostat housing but not to sure. The last first coolant leak was from the water outlet on the driver side of the motor. The lip that the o-ring set on disintegrated. Since the thermostat housing is plastic as well, I'm assuming its what's leaking now. Has anyone else seen this problem before or seen the easiest was to get to the housing? From me initially taking it apart it looks like a major pain. Thank you in advance for the help.

 

[JETaah]

Hello All,

I have got my 2nd coolant leak in the last month and I believe its the thermostat housing but not to sure. The last first coolant leak was from the water outlet on the driver side of the motor. The lip that the o-ring set on disintegrated. Since the thermostat housing is plastic as well, I'm assuming its what's leaking now. Has anyone else seen this problem before or seen the easiest was to get to the housing? From me initially taking it apart it looks like a major pain. Thank you in advance for the help.

It is labor intensive to change the thermostat on a CR car. Best make sure that is what is leaking first. I have not noticed that the housing is terribly prone to degradation but I guess it could happen.

Putting the lock carrier in service position is the least you can do to gain clearance to work on that area.

There is a way to remove the one screw that supports the coolant pipe that plugs into the thermostat housing without removing the oil filter bracket. It involves use of a stubby 6mm triple square bit and a wobble extension.

They sell the set of (Titan) stubby triple square bits on eBay for under $30 and, while they are touted as impact grade bits, I managed to ruin one just yesterday. The screw head survived but the bit didn’t. You might opt for the OTC set at around $60.

 

[greengeeker]

There is a way to remove the one screw that supports the coolant pipe that plugs into the thermostat housing without removing the oil filter bracket. It involves use of a stubby 6mm triple square bit and a wobble extension.

They sell the set of (Titan) stubby triple square bits on eBay for under $30 and, while they are touted as impact grade bits, I managed to ruin one just yesterday. The screw head survived but the bit didn’t. You might opt for the OTC set at around $60.

My trick for that bolt: There isn't much torque on it and a solid tangential hit on the OD with a hammer and drift will spin it loose. I then replace it with a water pump bolt.

 

[CodyR]

My trick for that bolt: There isn't much torque on it and a solid tangential hit on the OD with a hammer and drift will spin it loose. I then replace it with a water pump bolt.

Thank you guys for both your response. Is the water outlet on the driver side and thermostat housing the only in and out coolant path to the block? I got my phone in there yesterday and was able to see the leak. I’m guessing matting face between the housing and block

8BE0B05B-D420-4776-8A0F-DD6A11450B3A.jpeg

• CodyR
• Aug 12, 2022

Thermostat housing leak

here is how the outlet failed a month ago.

D3A63472-8454-47CF-BD71-F9F49E4911FB.jpeg

• CodyR
• Aug 12, 2022

Water outlet fail

 

[JETaah]

My trick for that bolt: There isn't much torque on it and a solid tangential hit on the OD with a hammer and drift will spin it loose. I then replace it with a water pump bolt.

Anybody that puts the same bolt back in is crazy.

 

[CodyR]

Found it, same as the water outlet. You basically have to take the whole front of the car apart to take it out. Car has 140k so if any is getting close to that, be prepared todo this.

56E70E96-62F0-4885-8569-255E0EB4A7C8.jpeg

• CodyR
• Aug 12, 2022

Thermostat housing fail

79D978CC-7E60-43E3-B05A-CD09D97DF016.jpeg

• CodyR
• Aug 12, 2022

Disassembly