I think there might be a blown head gasket. One guy I asked he said yes because last fall when he changed out my thermostat, he suspected a bad gasket. A guy that looked at it said he thought there was a crack in the intake manifold (?) and that Blue Devil would seal it up. Are head gaskets expensive to replace? If they are, is Blue Devil a good temp fix? If I use the Blue Devil, do you think it might last me for at least 4 months until I have the money to trade my car in? (it's an 04 Impala) It's not overheating per se, the gauge IS moving up past the halfway mark and there is water in the oil.