Was going to simply change my coolant and thermostat, but oh no!! Apparently there are two types of thermostats, one is a 190 degree, and I believe the other is a 174 degree? Which one do I use?

Thanks!

1997 X300

 

Use the 190

Cheers
DD

 

In a place like Arizona where quick heat up isn't an issue, I'd tend towards the cooler end of the range as opposed to the hotter. But 174 is a bit too cool imo. I run a 192 stat up here in Washington. I'd switch to a 180 stat if I were down there in Arizona.

 

Hmmm. I recently bought one from a Jag\Land Rover\Min repair shop (in multiple cities) that also has a parts counter. When I ordered mine, there was only one choice: 190*

GTS272 THERMOSTAT $16.57
NBB2217AC THERMOSTAT GASKET $3.90

 

The thermostat just removed from my 95 X300 is marked 88 degrees C which is 190 and it was clearly the original but that's in the chilly UK

 

88C/190F

Engines are designed to run at certain operating temperature ranges. It is generally accepted that efficient combustion occurs in the 190-200F range. Running lower engine temps leads to less efficiency and lower fuel economy. Also running cooler engine temps will lead to increased mechanical wear within the engine.

The purpose of a thermostat is to get the engine up to efficient operating temp as soon as possible. It controls the floor of the temp range NOT the ceiling because once a stat is fully open (about 200-205F) that's all it can do! It will not prevent overheating.

 

Autohausaz.com

Has 190 oem with gasket and o ring for $15

 

Agree with 190. But in my '95 XJ6 the O-ring wouldn't let the t-stat fit flush so I tossed it and made a seal with RTV. No leaks.

 

The thermostat I bought in the UK has that odd coating on the metal that allow a good seal without RTV and no O-ring. Cost me 6 ukp delivered.