M20 Running Cold?

[digger]

i have been running the 71 degree T-stat for 6 months. i haven't noticed any downsides with economy or anything else. and the engine actually runs at that according to the ECU reading from the blue sensor. i calibrated the ECU/sensor so i trust this more than the stupid gauge

[E30Gus]

That sounds like a partially clogged radiator and/or a bad fan clutch. The temperature should not climb that much while idling.

I recently put in an electric pusher that kicks on about half way up the temp gauge. My radiator and whole cooling system is only a few years old and i flush it regularly. I would like to know why the engine runs as cold as if I were to put in a 70 degree thermostat. Maybe I got a defective thermostat that is opening too early?

[jlevie]

I recently put in an electric pusher that kicks on about half way up the temp gauge. My radiator and whole cooling system is only a few years old and i flush it regularly. I would like to know why the engine runs as cold as if I were to put in a 70 degree thermostat. Maybe I got a defective thermostat that is opening too early?

While you could have gotten a defective thermostat, before replacing it I'd wand to know what the real temperature of the head is as measured by a contact or IR thermometer.

[E30Gus]

While you could have gotten a defective thermostat, before replacing it I'd wand to know what the real temperature of the head is as measured by a contact or IR thermometer.

Jim, what should the head temp be anyway at full operating temp? And I would imagine that I don't measure the valve cover, rather the sides of the head?
My neighbor has an IR gun that I can borrow this weekend.

[jlevie]

The head temperature should be very close to the rating of the thermostat.