Geo Prizm

I have a 1994 Geo prism sedan 136,980 mi. I have an overheating problem that we can't figure out. It only overheats in the summer. It only overheats while driving in town, usually if driving under 20 mph. This is what we have replaced so far: radiator, hoses, thermastat, tempature relay, fan motor, and checked wiring. Any ideas what else it could be?
July 8, 2006.

Try flushing the cooling system or it MIGHT even be your water pump. I had a Prizim and it did the same thing and it ended up being the water pump

Do a compression leak test to see if you have a blown head gasket.

Aug 8, 2006.