Reviews of OEM Volkswagen thermostat

I had my water pump and thermostat changed in August under warranty. I went for an oil change in Dec and they told me they think the thermostat is leaking. I told them they just replaced it 4 months ago. They went back and cleaned up the area around the thermostat and oil pan and said we need to monitor it to see if it's really leaking again. They were not surprised when I asked if it was possible it could be leaking again. They told me they see the part fail all the time.

Noticed coolant was low and could smell it sometimes. Dealership pressure tested system and found coolant leak at thermostat housing. Thermostat replaced under warranty. Its probably been leaking slowly for a year or more.

Independent mechanic noticed leak. Dealership confirmed the thermostat was cracked and leaking. Took a week for parts to arrive. Took a day to repair. All covered under warranty.

Bypass thermostat yellow arrow Included with radiator upper hose and you should be able to find the bypass by itself.

Parts 03F-010-501-B Sensor 04E-121-113-G

I could only find the thermostat from VW for roughly $45.

Bruce and I and my Dad replaced the thermostat, timing belt, water pump, and thermostat on the P. All went well, except that VW doesn't know how to do their job very well and got the wrong pulleys. But they did get everything else correct, and for a good price too.

I have owned my B6 since new and had the thermostat replaced under Warranty around 36,000 miles, at that point the slow warm up was causing the MIL to illuminate with a error that basically said warm up outside specification.

I'll throw a lower temp thermostat see if I can get her temp to stay low as possible for now

today I replaced the thermostat on my GLI too. What a pain in the ass!!! my back hurts so bad!. Anyways it took me almost 6 hours to complete the job. Now the car feels a lot more powerful, the old thermostat was opening at 80oC so it was overcooled all the time, heater just blew mild hot not hotter as it should and it was burning gas like a v8, It was doing 16-18mpg at most in city driving. I just checked with VCDS and the engine temp is at a solid 93oC constant temp, I took it for a ride for about 10 miles and it did 28mpg so I am pretty confident that the old thermostat just plain sucked. 6 hours well spent!