The fan did seem to be a little anemic but spins free - As I said I changed the control unit how would I test the fan out put? A bad water pump would overheat at highway speeds this one doesn't. The radiator seems to get hot all over so I'm betting there's no clogging - although the car is a 1997 it has low mileage - 60,000 and everything seems quite clean. Shouldn't you hear the fan spin up when the engine temp gets around 100 ? I don't hear any fan noise although you can see it spinning. There was some indication that octane makes a difference. I always burn 93 but when the oxygenate additives came in with the warm weather the problem got a little worse. I changed gas stations and that seemed to improve things a little. Hey what
happened to 97 octane I can't seem to get it here in New York City anymore. Used to be that Sunoco sold it - but no more.