consequences of not running a thermostat????

[Koshin]

My car has not thermostat, although I just ordered a nismo thermostat, I was wondering what adverse consequences not running a therm were?? I just got the car together a couple months ago and have not driven it much at all...It runs really rich and my mileage sucks, but other that that it runs rather well...Just a stupid question, I fix it tomorrow

Rich

[IanS]

I would bet it is causing the rich condition, as well as the poor mileage. Without the t-stat installed, one of two things happens

Either water flows to quickly through the engine. The coolant moves so fast that it does not pick up enough heat from the internal parts of the engine. This can cause hot spots on cylinder walls as well as poor cooling efficiency all together.

The second possibility is that too much coolant flows through the engine. So much so that it removes too much heat and the engine never properly reaches operation temp. The gauge may read correctly but the ECU always sees the engine as being cold. It stays in cold idle enrichment, adding extra fuel.

I would replace it ASAP, as well as flush the coolant.