Thermostat MISHIMOTO or OEM Volkswagen

I have a mishimoto thermostat with their radiator setup. It does kick on the fans on at a lower temp range than when the stock one would which is good. I had issues running hot on the stock rad/thermostat and haven't had any issues since.

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.

I replaced the thermostat with a Mishimoto thermostat and vaccume filled the coolant. I did a 30 min test drive in the 95+ weather with the AC cranked. Never went past the 7th dot.

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.

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.

when installing a mishimoto thermostat, check that the shoulder/flange is the same thickness as oem. Otherwise your stock hardware WILL NOT FIT. You will bottom out the bolt in the timing cover and snap that mf. Those bolts are extremely hard to access and a MAJOR HEADACHE to get extracted.

mishimoto changed the design of the thermostat when I purchased and you will need shorter bolts they are not provided

I got a bad mishimoto thermostat with similar results.