Over heating

[RBnWA]

Drain some antifreeze to see top of tubes. I wonder if tubes are plugging up with calcium . Coolant flowing to fast it will not cool right. Coolant flowing to slow will not cool right. If the tubes are plugging on the inside coolant will be flowing to slow. RB

 

[MarkB_MI]

A word of caution if you decide to change the thermostat: Since it's mounted vertically, it will tend to slip down out of its groove. This can result in a broken housing when you tighten the housing bolts. Use a piece of fishing line to hold it up while you tighten the bolts.

 

[Texasmark]

A couple of hours is a long time under load to some tractors. Something easto check...How tight is the fan belt?

A loose belt is easily overlooked but a good source for overheating when you have a clean radiator, the coolant passages inside the radiator and engine block are clean, and the thermostat is functioning properly. I had a JD 4230 with cab and AC and the belt had to be really tight to spin the fan correctly to prevent overheating. The rule of thumb, something like 1/2" of deflection with your finger between the alternator and the crankshaft pulley didn't apply to that tractor.

I recently bought an '80's tractor and part of the prep. for my use was going through the cooling system which included a flush, 50-50 fluid, new thermostat, sending unit and dash display. On an early usage of the machine mowing with a good load on the engine, the needle moved into the red zone. Checked this and that and no obvious reason. Got out my non-contact Infrared thermometer and shot some temps around the engine and the engine was doing just fine as was its cooling system. The next day I was out mowing again and it stayed out of the red zone.

In putting more mowing time on the tractor I found that the indication on the dash panel would be in either of the two directions. Knowing its the instrumentation, not the actual cooling, I just disregard it.

 

[Ozlander]

I mow a 6 acre field with an 860 and 6 foot brush hog. Grass and weeds 3 or 4 feet tall.
Engine rpm at 1800.
Even on a 100 degree day, I don't see any overheating on the gauge until a get some grass and stuff on the radiator.
Drop the grill and brush it off and good to go until it builds up again.
Once in a while, I flush the radiator from the back side with a hose.