I have a 92 civic ex and the other day I was driving and the engine started to choke. A few minutes later white smoke was comming out of the exhaust like crazy. I was burning prestone. After all the prestone was gone it ran fine but it started to overheat(obviously). Now I'm working on taking my head off because I think it's a head gasket. The car is old (250ks) so it's a pain in the a?? to take all the parts off. There is no prestone in my oil or vice versa. I just want to know if it's a head gasket or am I wasting my time. When I started it this morning it was running fine no pigging or knocking. I figured it was the prestone in the chamber(s) that was making it choke. Please reply because I don't want to spend all these hours taking the head off if the block is done. There is also no leaks where the head gasket is located but I figured it could be broken on the inside.