John Deere 4620

[Farmall m farmer]

Are John Deere 4620 took a dump last spring we had it on the manure pump and the guys hauling manure said there was fuel dumping out the crank case breather I checked the oil it’s over full and full of fuel I looked the antifreeze I could not see it in the radiator I haven’t started tearing into it probably a winter project I’m just curious what the professionals thought was wrong I think it blew the head gasket

 

[JD Dave]

The problem could be as simple as a failed fuel transfer pump as described as a hole in the diaphragm causing fuel to leak into the crankcase.

 

[Jim.ME]

Blowing a head gasket would not fill it with fuel. Most likely if it is mostly fuel and no coolant in the oil, JD Dave has the likely culprit. much coolant in the oil and it would seem like it would have been chocolate milkshake running out the crankcase breather.

A bit of checking will give you a real idea compared to everyone guessing at what it might be. Change the engine oil and filter, what comes out when you pull the drain plug? Thin, black fuel smelling oil or chocolate milkshake oil and coolant. Get the coolant to the proper level in the radiator and pressure test it. If the draining gets just oil and fuel, I suggest change the fuel transfer pump, run it, and monitor the oil level. If it has coolant in it and the pressure test doesn't hold, then you start looking at head gaskets, sleeves and sleeve seals, and the oil cooler. Two or three hours investigating and it might be working again.