No improvement from the oil indicates the rings are OK, you've got valve seat issues. You've probably got a leaking riser gasket allowing coolant to leak into cylinder # 4. Look at the gasket between the riser and the manifold, one side should be scalloped between the bolts, the other side should be straight, if its scallop on both sides, you have the old style "bad "gasket. Figure a head job, Not too difficult job, cylinder head will have to go to the machine shop
|