Hi, thanks for quick reply. Vent is open. It doesn't seem as responsive to the foot pedal as it once was, although I haven't used it a lot lately. I drive transport, so am not home a lot, but it seems to bog down. I wonder if there could be something wrong with the fuel itself, like water in it. Could I use the conditioner I use for the truck in the diesel? Should I start another thread for the other problem I'm having with it? There is oil in the antifreeze, and I was thinking head gasket. The rad cap had oil on it and there was a film of oil on top of the antifreeze. This only happened once last summer. My son was driving it and he revved it up quite high while we were cutting a tree down. Had a line from the tractor to the tree to make sure it fell away from the house, and he gunned it. Shortly after that, I had checked the tractor out and found traces of oil in the rad.