Last fall I rebuilt a JD G for a good stock puller. 125 over, took the head down a bit and smoothed the head and manifold out good on the inside, nothing drastic. I have done this many times. When I got the tractor running I almost instantly started getting antifreeze in the cylinders fairly bad. The head and block were both checked before any work was done to either. Its bad enough that it ruins plugs when you try to start the tractor, the plugs wont fire anymore. I drained it for the winter and havent had time until recently to look at it more. I used the black sealer on the head and manifold bolts to seal them when I put it together as I have done before. Thought maybe a bad head gasket so I changed that and it didn't help a bit. If I were getting leakage into the cylinders shouldn't that make pressure in the radiator when it is running from the compression in the cylinders? The radiator stays calm and still when its running. I'm wondering id I got a hole when it was bored from a thin or cavitated spot in the block. Just looking for ideas before I tear it down again. Thanks