JD 4300 overheating

[swampbuggy77]

I have a JD 4300 that overheats within about 5 minutes of first crank. I'm assuming this is the thermostat that likely needs to be replaced?

Belts look fine, plenty of coolant.
Anyone know if the JD thermostat M811034 would be interchangeable with something I could get at the auto parts store?

Anything else I should test first?

Thanks!

 

[ruffdog]

Just be sure you can see through the finned area of the radiator as dust can build up and clog it.

 

[jthibodeau89]

Yes, there is a grass screen behind the hydraulic cooler and in front of the radiator that gets clogged. Not sure if all model trannys have the cooler. My HST does.

When i replaced my leaking water pump i found that a previous owner had removed the t-stat. I just ordered one off the internet.

 

[rekees4300]

Anything else I should test first?

Thanks!

Also test the coolant itself. Those kits are just a few dollars.

 

[CoyPatton]

There was a product called radiator genie available a few years back. I have not seen it advertised recently. It had 2 wands for clean the radiator. One for air and the other for water.
Regardless, keep a clean radiator of dirt/dust especially grass seed for brush cutting is very important for the cooling of tractor.

 

[swampbuggy77]

Thank you for the advice everyone. So I drained the radiator and pulled both the thermostat and temperature sender.

The thermostat appears to function normally in boiling water.
I happened to have an extra new temperature sender to compare to, and measured the resistance between the terminal and body at both cold and boiling water temps. They both were near identical, and met the 40-400 ohm spec in the repair manual.

I'm running out of options as to what the problem may be?
Could it be the thermostat was just stuck and is now working fine after taking it out?
Could it be the water pump?