Thermostat MISHIMOTO or OEM Nissan

After reinstalling an OEM thermostat, I am very happy to say my high temp issues have been solved!

We had to replace thermostat from Nissan group Infinity. So far no problem right now

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.

Just make sure you buy a genuine Nissan thermostat. I don't know what it is about these cars, but they do NOT like aftermarket thermostats. Just spend the extra ten bucks on a Nissan part.

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.

When I stuck the key in the ignition, the temp needle pegged the far end of the hot zone. AAA towed it to the Nissan dealer and they put a thermostat it in for $50 or something and it worked perfectly after that.

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.

I bought and installed a Mishimoto thermostat that activates at 68°C, while my vehicle OEM (Original factory) thermostat activates at 88°C and fully opens at 100°C. With the Mishimoto thermostat (68°C), the coolant temperature basically stays 71 ~ 74°C when driving, from OBDII reading. Short Term Fuel Trim was OK, between -10% and +10%. I checked the spark plugs after one week, they were fine.

However, after three weeks (last Saturday to be precise), the Check Engine Light was on when I started the vehicle, and OBDII gave Code P0128. I searched the code online and got: coolant temperature fails to reach the proper operating temperature, or Coolant Temperature Below Thermostat Regulating Temperature. My thinking was the engine finally realized that the temperature was below the operating temperature, due to the Mishimoto thermostat.