Thermostat Mahle or OEM Volkswagen

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.

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.

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!

I've had that occur - it was a bad thermostat. It would stick very slightly open. At idle, or in city driving, it was not noticeable. However, on the highway, the gauge would start to drop and the interior of the vehicle would get colder.

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

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 just be replaced mine for the low regulating temperature, and the snag seemed to improve, but it will still pop up and the car is slow to hit temp, slower than it was last winter at least.

mine is also a problem an my car is 1.5 yrs old. Sometimes the temp gauge acts as if it is -40C outside even if it is a couple degrees above freezing. Often the car will take 4-5minutes to get near base idle when it is cool outside, but when it's really cold, sometimes it takes 30seconds and there is no way it's warmed up. Can also smell coolant anytime I open the hood. Sad.