Thermostat Wahler or MISHIMOTO

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.

Replaced the new Mahle/Behr one with a new Wahler one, and now it runs at 97° under low load and 80° under high load, as it should, and seems to be fine.

I replaced the thermostat myself. It’s in a pretty bad place, hidden under the intake manifold. It took me about 3 hours to get the job done, had to use a mirror to see the screws. Mine was stuck open so the car in winter time wouldn’t even reach 190 F. I bought an OEM Wahler 07K121113B thermostat from Amazon for like 30$, so far has been working great.

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.

I had 2 fail back to back. The first lasted 3 months, a couple thousand miles, the 2nd lasted 5 weeks, also a couple thousand miles. Left me stranded. 275 degree spike followed by coolant puking.

Thermostat was ALSO replaced when the water pump was, with a Wahler unit. Guess I got 10k miles out of it?

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 had two Wahlers and they leaked as soon as I fitted them. In exactly the way you described.

I got the wahler one in 2019, that would explain the really slow leak I have.