John Deere 750 CUT Radiator

[sandman2234]

Check belt condition and tension!
Can you remove radiator cap, then warm engine up and watch for coolant movement?
If no movement, consider a waterpump removal to check if blades have rusted away. Just a little work and a gasket.
Flow at radiator neck will tell you a lot!
David from jax

 

[loggin]

Some more details

I got my hands on a cooling system test kit. I loaded it up to 15psi, the tool didn't hold that great, but I managed to seal it and it held 13psi overnight, so no leaks there, or at least nothing serious. Rad cap seems okay too.

I'm no diesel expert, but what else could be causing it to overheat like this?

I'm going to take the valve cover off at some point and see if anything is broken, and do a pressure test also.

cheers
xp

How many hours are on the machine? Have you looked at the water pump and thermostat? Sometimes a thermostat can get a little sticky and not open all the way.

 

[sandman2234]

Hours on the machine probably don't make much difference, especially if thermostat and waterpump are in good shape. Best way to tell that they are working is to remove cap and warm it up. If there is flow when temp comes up, thermostat is opening and waterpump is pumping. Then a thermomter in the radiator neck to compare radiator coolant temp to block coolant temp, which is what gauge reads.
David from jax

 

[xp190]

I replaced the thermostat about 2 years ago, and had the water pump out, it was all fine back then, but I will put the pump back on my suspect list until I take it off. I'm planning some disassembly, just need my seals to get here first.

Pressure and vacuum test of cooling system showed no leaks, belt is tight and brand new.

I also adjusted the valves, they were a bit tight.

I'll have to keep at this until I figure this thing out, seems like a very simple but well put together engine.
I tried pulling the injectors, they are stuck good, not sure if they were ever removed or serviced.
Hoye has a tool for pulling them as well as an adapter for a compression test, I'm considering ordering them.

The hours I have to check, I think it's something around 3700.

Also, I made a mistake earlier it's a 3T80UJ engine, not 2T80UJ

xp