Thermostat IN or OUT

soupy_sam · Post by **soupy_sam** » 08 Feb 2005, 00:07

Does it make a great deal of difference if the thermostat is left out of the engine?

weety · Post by **weety** » 08 Feb 2005, 01:18

the thermostat is there so that your car can a) run at a nice temperature for the engine and b) so you can have warm air in the cabin.....basically all the thermostat does is restict coolant flow (when cold) to just round the engine and heater matrix....as the temperature rises to around 80 degrees the thermostat opens and the hot water can run through the radiator to be cooled...... as the water temparature drops the thermostat closes etc etc etc....if you have no thermostat the coolant just circulates through the radiator all the time making the car and you cold!

bikeboyz · Post by **bikeboyz** » 08 Feb 2005, 01:46

It will do nothing for your fuel economy either as on short journeys your engine will not be operating at an efficent temperature.

splez4 · Post by **splez4** » 08 Feb 2005, 02:08

engines wear out quicker when running cool, also some engines need the thermostate to get the correct circulation around all parts of the cylinders, some merks and bms have been known to sieze on one or two cylinders with out a thermostat in

alan s · Post by **alan s** » 08 Feb 2005, 02:50

I've just changed a thermostat in a TZi 1.9 petrol as I felt it ran constantly too cool. It always sat on around 70.
When I pulled it out, I noticed it seemed to be at around 90% of the height of the new one. With the new one in, it goes at 90 constantly and we've found it to feel smoother overall and an improvement in fuel economy which seeing as I'm in the tropics should be a fair indication of what effect it should have on your fuel economy.
Alan S

oilyspanner · Post by **oilyspanner** » 08 Feb 2005, 17:38

You need the thermostat in there, the motor can easily overcool and run at less than maximum efficiency,overcooling results in mayonnaise in the engine, poor heater performance. then consider that the alloy head is designed to expand at working temperature more than the steel bolts that hold it on, this results in the bolts being effectively loose.
Stewart