135 Diesel coolant temp

[bcny]

Assuming the cooling system is working well, and the tractor is under moderate load,
what would be the measured coolant temp at the top of the radiator?

Does anyone know how that usually relates to the thermostat opens at rating?

I don't trust the dash temp gauge and want to use my calibrated industrial thermometer to verify.

Thank you.

 

[Dieseltech]

Long as it's just under 200 degrees I'd say it's fine..

 

[Clarkbug]

Are you planning to open the radiator and measure directly? Wouldn't that depressurize the system and mess with the readings? Or are you going to measure the surface temps of the radiator?

 

[Jim.ME]

What type of thermometer is your "calibrated industrial thermometer"?

The top of the radiator should be close to the temperature of the coolant passing through the thermostat once the thermostat opens, it will not be the same for all thermostats. The opening temperature will vary with the design temperature of the thermostat. If you want to check your tractor's gauge for accuracy, I would recommend a non-contact thermometer and check right where the thermocouple is mounted in the engine, as depending on the location the temperature may not be the same as at the radiator.

 

[Indiana Ken]

(quoted from post at 14:43:04 07/04/21) Assuming the cooling system is working well, and the tractor is under moderate load,
what would be the measured coolant temp at the top of the radiator?

Does anyone know how that usually relates to the thermostat opens at rating?

I don't trust the dash temp gauge and want to use my calibrated industrial thermometer to verify.

Thank you.

As you stated, thermostat rating is the temperature it begins to open. Therefore, when the thermostat just begins to open one could expect the temperature in the top radiator tank to be at or slightly less than the thermostat rating. This is because the flow rate is very low at the "cracking open" point and some cooling could occur between the thermostat and your measurement point.

Now, the problem is what is the thermostat opening at moderate load or what is the actual definition of moderate load for a 135. My point is, I don't believe this test condition is definable.

Perhaps you want to test the thermostat in a pan of water on the stove using your industrial thermometer. Verify the cracking point of the thermostat and the full open point. Be sure the thermometer is maintained at it's specified immersion depth for accurate readings. Now, the thermometer in the radiator tank can estimate the thermostat cracking point and the full open point. Once the tank temperature equals the full open point temperature the thermostat is full open it is no longer in active control of the coolant temperature.

You did not state where the dash temperature gauge is taking it's reading. If the measurement is taken at a location different than that of the industrial thermometer you may need to account for that difference.