Was not to sure where to put this but wanted to share the information. Part #21200-4W000 is a OEM thermostat that opens 10°F sooner then the stock thermostat. I confirmed this by dropping the massive $18 for one of these thermostats and testing it in some 170°F water. Turns out it does indeed start to open around 170° and was fully open by 175°F.

10°F might not be much to many but to some it's just enough and also gives extra option for thermostats for us as the Mishimoto (begins to open at 155°F) has apparently been universally hated by the 370z community for being a not so great product in the reliability department.

And yes: this is a direct bolt on/swap. I did a few searches and couldn't find the part number on the forum so this is mainly for future searches.

 

Great find and appreciate the info hunting. Anything that helps keep these VQs cool helps.

 

I believe this is the one that came on the 2008? As I believe I read somewhere that the 2008s had thermostats that opened earlier than later models.

 

No worries.

And yes, It was in the 2008 coupes and used on a few other engines including most all VQs in the middle east market.

 

I thought the stock one was 195°F? Probably hotter temp for emission purposes. Wonder what other negative side effects might result with running a cooler thermostat?

 

Stock is 180°F (according to the FSM). You see full open around 185°F which will give you about 190ish°F temps most the time on hot days and long drives. Last week I got up to 203°F just on the commute home. When I swap out mine I will do a test on the stock thermostat.

 

this is very helpful info...the 10 Degree drop may just make it a more liveable thermostat year round and be helpful in the summer...that 155 degree Mishimo sounds problematic especially if you leave it in in the winter and aren't tracking the car.