4020 oil in radiator

Have a 4020 serial 76000 oil in radiator. Is it possible the gasket on lower end of cooler has failed or do the coolers fail? Cooler looks pretty robust. Looking at parts diagram it looks like the lower end gasket could cause this problem. We do not have it apart yet. also need to address oil leakage at head gasket. Any suggestions or just do the gasket.I see YT has a head gasket set.

I thought by now one of the Deere experts would have answered, and you might want to post on the Deere forum below. Could get some model specific answers there.

But I can give some generic guesses...

Oil coolers do leak, and when they leak they put oil in the coolant 'cause the oil is under more pressure than the coolant. One way to test it is to bypass the coolant around the cooler, take the tractor for a light duty test run and see if oil leaks out of the cooler.

The head gasket can leak oil into the coolant also. It can leak from the pressure galley that brings oil to the rockers. If there is oil coming from under the head, and you're sure it's not running down from a leaking valve cover gasket, good chance some of the oil is also going into the water jacket. So if you're seeing oil coming from under the head, that needs to be repaired.

The oil that's in the coolant, that needs to be cleaned up too. Oil will attack the rubber in the hoses, swell them from the inside out. Getting oil out of the cooling system can be difficult, it tends to cling as the coolant is drained, then float back to the top when refilled. Best way to get it out is to float it out with a slow running overflow from the garden hose. Get the engine up to temperature, put the hose in the radiator, crack it open just enough to slowly overflow. Then drain it, refill with just water, add some liquid laundry detergent, or some dishwasher detergent, run it for a few days, drain and repeat until the oil is gone, then drain and refill with antifreeze mix.

Hope this helps...

Thank you Steve for your input! I have taken your advice and reposted to J D forum. I was not aware head gasket might be an issue. This one is definetly leaking. Since he has hay done for now we have a little window to tear down.

Is the water black or gray milky looking ,if black
and slick ,it most likely soot from the gasket leak.
If gray ,most likely oil .

george