I have a problem with my licoln over heating , what could it be? on 1990 Lincoln Town Car

My 1990 lincoln towncar is over heating , i have replaced the thermastat and have found no leaks. the radiator is circulating fine and the water pump works. The oil does not have water in it. It heats up when I have been driving it for over about 15 to 20 minutes. What else could it be?

Asked by for the 1990 Lincoln Town Car
When you say it is overheating and it "heats up" - do you mean there is a gauge that reads high? Or does it actually boil over?

This engine (302 cu In. / 5.0L) is not one that commonly has cylinder head or gasket failure, so I'm likely to rule that out. I would make sure the fan is turning as it should.

If it is the gauge that is reading high, you may have a temperature sensor issue.
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You may have a fan clutch going bad. If you have gunk onthe front of the fan clutch, that means its leaking the special silicon out of it.