Do engine temperature fluctuation and heat problems indicate radiator problems?

Thermostat is sticking and it is going to stick closed in a little time so get it replaced. dont cost to much the stat is about 7 or 8 dollars , getting it put in could cost 20 or 30 dollars, they do this in very hot weather or when cold weather starts!

I would be concerned of a head gasket problem. the symtoms of fluctuating temp gages is a good indication. you probably would want to get your coolant sniffed either with a gas analyzer to see if there is hydrocarbons in your coolant, if there is the head gasket is going to have to be replaced and the head would have to go to the machine shop to check for cracks, and to have it pressure checked and to resurface the mating surface. you can buy a tool at the local parts store that is called a combustion leak tester. this will do the same as a gas analyzer but not as well, but it does work fairly well. also when warmed up feel the radiator hoses to see if they are firm, if not you probably have a radiator cap issue, where the cap is not holding pressure. you might want to put a coolant system pressure tester on the system to verify thaat you do not have any leaks. if you have sweet smelling white smoke coming out of tailpipe this is another indication of a head gasket issue. make sure and check the engine oil to see if it might be way overfull or goey and white this would be an indication of head gasket issues as well. if the head gasket is bad it is a fairly large job to correct. well here are some ideas good luck and i hope it is something simple for you.