Overheating or What?

[bc realtor]

I have the Antonio Carrero ttr4400 with the yanmar 3cld engine. have an issue with the thermostat I thought yet now I have the thermostat replaces and the engine is going into the red again.. I have used my temp sensor on the thermostat area and it reads 10 degrees below the temp marked on the tthemostat.
Am I missing something or what?

 

[bc realtor]

Just to let yoou know, it takes about 5 minutes for it to go from the green zone to the red zone on the temp guage.

 

[bc realtor]

I also can operate the tractor without the thermostat and it hovers just below the hot range but stays in the green?:confused2:
Do I just throw out the thermostat and go back to working the tractor without it?:anyone:

 

[boomer1025]

I'd try replacing the temp gauge sending unit

 

[bc realtor]

This is getting fun now. There happens to be two sending units , one below the thermostat and one above. I moved the sensor wire from the one below to the one above and went mowing for a few minutes. then I heard an autable alarm sounding but the temp was in the green. I switched the sensor back to the lower unit and it stopped the alarm but seemed to be in the green for temp range:confused2:

 

[bc realtor]

is there any way to test the temp sensor? I have tried the laser digital thermometer on the housing and it seems to be measuring about 8 degrees below the themostat temp.:anyone:

 

[boomer1025]

You can test them, if you know what the OHM's reading are at different temps. There a thermistor, the warmer they get, I the lower or higher the resistance reading you'll get from it. trying to find the spec's for one is the problem.
PS I would run the engine without a thermostat for very long. On some engines, running without a t-stat will allow the coolant to circulate to fast an cause an overheat problem