Fan clutch on 89 F150 4.9
09-24-2012, 02:02 PM
#1
Fan clutch on 89 F150 4.9
Hi again, When I first start my truck I hear something making noise and it sounds like a bearing on something in the front of the engine. The last time it made that noise, it also chattered like a machine gun, then eventually quieted down. A mechanic told me that my fan clutch was bad, but when I grab the fan blades and try to wiggle it there isn't any excessive play it it or the water pump (with the serpentine belt off). Is there anything else in the belt area that would chatter like that? The alternator melted down right after that, (G2, replacing with G3 on Wednesday), but I don't think the alternator would make a machine gun type of chattering, would it? I also tried wiggling the belt tensioner, and it spins smoothly and has no play. I know that fan clutches are cheap, and I'll replace it if it sounds like the problem. Thanks, Bill
09-24-2012, 03:06 PM
#2
Senior Member
Spinning the accessories was a good idea, however useless for the fan clutch and some noises only occur under tension. The fan clutch should turn freely with slight drag when cold. Check Chiltons for the proper procedure, but to test the fan clutch you cover the radiator with cardboard with a hole where the fan clutch spring is ( center ) to allow air to flow over the spring. Run the engine until engagement temperature. ( 200*?) Then turn off the engine. The fan should be hard to turn. To track down the noise use a stethoscope or a piece of hose. Harbor Freight sells stethoscopes for around $10. They are very handy.
09-24-2012, 11:14 PM
#3
fan clutch noise on my 89 4.9
Thanks for the information. I'll try that (as soon as I get my G3 alternator and wiring) 
Ole Red is sitting in the driveway minus the crunchy, burned connectors and wires attached to the alternator.
I would also like to know if anyone out there has heard the chattering from their fan clutch. Is there anything else that could make a noise like a machine gun, like I heard?
It was definitely up there where the serpentine belt is running. I also found out that the belt tensioner and pulley were replaced 20,000 miles ago, and appears to be solid and smooth. Thanks again.
Ole Red is sitting in the driveway minus the crunchy, burned connectors and wires attached to the alternator. I would also like to know if anyone out there has heard the chattering from their fan clutch. Is there anything else that could make a noise like a machine gun, like I heard?
It was definitely up there where the serpentine belt is running. I also found out that the belt tensioner and pulley were replaced 20,000 miles ago, and appears to be solid and smooth. Thanks again.