Mishimoto MMTS-MB55-03L Racing Thermostat Compatible With Mercedes-Benz E-class AMG 2003-2006

Quality Mishimoto, great product.

First of all, this thermostat work as advertised, it lowers operating temps a few degrees from stock on my 2006 S350 (M112 NA 3.7L). However, to get the full benefit, and to "fine tune" it, you should calibrate fan trigger temps through SDS or other scanners capable of doing this. I have my fan set to start spinning 7C sooner from stock, and I may actually set it to 10C, which is the max allowable by the ME unit (ECU).Now, this thermostat WILL fit the non kompressor engines, BUT, you will need to modify the stock thermostat housing slightly. What you will need to do is drill the thermostat housing pin hole, the one at the back where the thermostat sits in. I don't recall exact drill bit size I used, just see which bit size fits the best in the hole. Then, drill it just 1-2 millimeters at a time, and test fit the new thermostat. As soon as the thermostat sits flat against the housing, don't drill any deeper. Don't forget to wash away and clean the metal shaving, you do not want those in the cooling system! Then, it's just a matter of twisting the thermostat locking tabs into place, install onto the engine, and you are all done.