I have a John Deere 2020. It leaks coolant into the oil. Let me tell you some history on it and what happened.
This tractor has been in my family since it was nearly new (in the '60's). It had been used hard and abused. Several years ago, My dad got it from my grandpa to use on our young sod farm. We fixed it up a little and used it to run a 15 foot tri deck finish mower to mow 50 acres of sod. We used this tractor for 2 or 3 years but it finally was too tired to run very good anymore. So we sent it to get a complete engine rebuild. It got new sleeves, pistons, ground crank, new bearings, I don't remember if they completely rebuilt the head or put a new one on it. anyway, I think it was a out of frame complete rebuild. (it better have been for $7000!)
A year or so after the rebuild, my little brother was mowing with it and the the shaft that runs the hyd. pump in the front wore a hole in the bottom of the radiator and it lost nearly all it's coolant and he ran it till it overheated and quit! We changed the oil, and fixed the radiator and it still ran fine. For the next few years, I must have pulled that radiator and had it fixed or tried to fix it myself, 3 or for times because it kept leaking. Last summer, I forgot to check the coolant and went out to mow and it overheated on me because the water had leaked out again. I noticed the gauge was on the red zone and I shut it down. since then, it started leaking coolant into the oil. Oil does leak out of the head gasket ( I think it started with the first over heating) on the right side of the block (I'm guessing that's the cam side). It does have some blow by but It still runs good. I'm guessing it's not leaking into a cylinder because it doesn't blow white smoke or pressurize the cooling system.
Is it just the head gasket? are these blocks/heads known to crack when they over heat? could there be damage to cylinder walls/ pistons from overheating? It has a brand new radiator now (should have done that in the first place years ago!
) The motor only has about 2,000 hrs on it since the rebuild. The problem is I have no back up tractor. It looks like a head gasket can be done pretty fast but if I discover a crack or a more serous problem if I pull the head, then I'm with out this tractor that I depend heavily on.
Thanks for your help!