My car has this problem where It would not let the car start up (It would crank, just not start) I put some water into the radiator, and the problem would fix instantly. I thought it was having a radiator leak somewhere, so I checked all over, but couldn't find anything. The car was taken to Pep-boys, and the people said that they had found exhaust fumes in the radiator fluid, which they said meant a damaged head gasket, and therefor water had been making its way into the piston chamber. The weird thing though is that the car runs perfectly normal (as far as I can tell) no stalling out, no loss of power, it doesnt run rough and I can't see any steam coming from the exhaust. The problem had been going on for about a week or so before It was taken to Pep-boys. Anyone got any ideas about what the problem could be?