I am having trouble keeping my daughters 850 from overheating lately. Had been running it unpressurized for awhile because of a crack in the tank of the radiator and was not overheating even in traffic. THEN all of a sudden you can't go three miles without steaming the fender. I've replaced the thermostat and temp sensor below it and no change except the service light went out (blinks on and off,every now and then instead). My guess is the cooling fan is the culprit, is there a quick way of testing it? ( I've got it out, finally replacing the radiator)Any help with this is greatly appreciated.