Does oil in the radiator of a 1993 Geo Prizm mean you have a blown head gasket or is something else wrong?

Answer 1

sounds like a blown head gasket or a cracked head. It could be a number of things and none of them are good. Most likely a crack in the head. If it is over heating this is probably the case. I have a 94 Prizim that at 99,000 miles began with oil in the coolant/antifreeze then shortly after this discovery it developed an engine knock followed by oil pump failure. This would be the fe4e 1.6L engine. In researching a replacement, I came across what turned out to be a very valuable bit of information. The original motor can be replaced with a Japanese import engine fe5e 1.5 lit ire. It bolts right in and looks the same but it cost 1/5 the price of the 1.6L. I paid $160 for a used 1.5L. They wanted $700 for the 1.6L. These motors are imported from Japan with less than 40,000 miles on them. I just put my wires, distributor, and fuel injection on it, it started first try, and runs like new. It is a little bit underpowered but not that bad and I am getting no less than 30mpg for fuel consumption that is better than when it was new.

If it's an Automatic, it could also be a bad radiator, with ATF leaking from the trany cooler.