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What do you think?
93 bronco 5.8, 122000 miles. daily driver runs perfect. Today while driving to work it ran hotter than the norm on the freeway (not overheating) It seems to cools down in the city or coasting. coolant fine, waterpump without noise or play, but I did notice that the fan spins rather easy and with the motor running at 2-3,000 rpm the fan doesn't pick-up speed. Is this norm or is the fan clutch shot. thanks ripa
With the engine cold, if you hand-spin the fan, you should get maybe one to one-and-a-half revs. out of the fan not much more. If you get more than that the clutch is suspect.
With the engine running, you should be getting a good blast of air back from the fan at idle. WINDY would be the best description. Less than that...again...clutch.
Sounds like clutch to me but those two items should give it away for certain.
Thanks the coolant was flushed 4,000 miles ago-I changed the heater core and decided to give it a flush-thanks again I will check the fan in am when motor is cold.
I would definitely look for blockage or a stuck thermostat. On the freeway you could lose the fan completely and not have any problems. I run electric fans on my 1990 and they never kick on on the freeway, unless stuck in traffic of course. Sounds like you are not getting enough coolant flow. Air flow is taken care of by the 55+ mph winds you are creating while driving. Let me back up one minute though, check the radiator and make sure the fins aren't blocked, bent, clogged up with bugs etc. If they were, I still think you would see cooling problems on the city streets as well.
FYI,
Thanks for all the great tips. I found the problem and though I should post it for everyone to keep it the back of their mind. The small formed outlet hose from the thermostat housing developed a small tear on inside lumen => which formed an outpouching in the hose and this became larger with high pressure and partially blocked coolant flow. thanks ripa