Thermostat OEM Audi 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.

I finally got around to installing a new thermostat/o-ring/housing and coolant reservoir/cap yesterday. When removing the thermostat, I noticed that the bottom bolt was VERY loose... I had done the thermostat without housing about a year ago now, had never leaked coolant before... My best guess is that I just didn't torque it enough and it slowly loosened, but only when cold (just a guess, but would help explain why no drips when car was running on ramps) and in small enough amounts that I did not notice a puddle on the ground.

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 had a 96 and have done that job twice, make sure replace the thermostat otherwise it's a do-over several months later because you tried to save $20. Been there etc!! Change the belt, tensioner, water pump and thermostat.

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.

The current plastic thermostat looks a little more beefy, but is still shatty plastic. They're commonly failing at 30-55k miles in the stuck closed position, instant overheat.