Running without thermostat

Typically the coolant will not stay in the radiator long enough to be cooled because the coolant runs right through. The thermostat many jobs first it control the operating temperature of the engine next it regulates how fast the coolant can travel throughout the system.

Engine parts wear in the first five to ten minutes of driving after starting a cold engine. You will be holding the engine temperature in that cold range where wear takes place so the engine's life will be greatly reduced.

You aren't solving any problem by leaving the thermostat out. Also, the Engine Computer goes into "closed loop" when the engine is above a certain temperature. That is when it adds the oxygen sensors' readings to the fuel metering calculations and fine tunes them for best fuel mileage and lowest emissions.

If this goes on long enough, it's possible to set a diagnostic fault code for "Engine running cold too long". On some models that will turn on the Check Engine light. That can turn into a big problem because if a totally different, minor problem is detected, you won't know it because the light is already on.

Please let us know if you need anything else to get the problem fixed.

Cheers