While taking apart my old engine today, I noticed that there was no thermostat at all.

My question is... isn't that what the temp gauge goes off of? The temp gauge seemed to work just fine while the engine was in use...

thanks,
fikshun

 

No, the thermostat is what controls the temp.your engine runs at. IN theory, the cooling system of an engie is designed to cool it *to much*. This allows for really hot days, and system efficiency decline over time. SO you need a way to make the engine run at a certain temp all the time, thus the thermostat. IT is a heat sensitive valve that stays closed(keeping water in the engine until it reaches a certain temp) and opens only when water in the engine is at operating temp, this regulates overall temperature. Running with no thermostat means it should have been very cool. Most people take out thermostats when they have major cooling system problems, such as bad coolant seals, since the backpressure/restriction the thermostat poses puts stress on the system, and it can sometimes be a quick bandaid to mask a larger problem until it can be sold etc. By taking the valve out, the system is free to cool a bit more than it otherwise would, and any leaks, internal or external, will have less stres placed upon them due to the valve being gone.

 

So is it a good idea to take it out??

 

It is a bad idea to take it out since it regulates the temperature. When running w/o a thermostat, the coolant flows too quickly and doesn't have enough time to cool, basically. The thermostat keeps the temp within a certain operating range. The temp gauge is read off of the sender near the rear rotor's spark plugs, next to the oil pressure one(gold circular mushroom deal). The ecu reads the temp for its fuel mixtures off of the sender near the thermostat(in the back of the water pump housing.)

moral of story=put a genuine mazda one in from the dealer.