I've got this whining noise that is only heard when engine is warm from 1900 to 2500 rpm. If got a 2000 f-150 5.4L I removed the belt and started it warm and theres no noise. Its also got a ruff idle but is not there when the belts off. All the pulleys spin fine except the idler but i wd-40 ed the crap out of it and spins fine now any Ideas?

 

Putting WD-40 on the idler pulley will only work for a very short time and not once you load it up by reinstalling the belt. If the pulley turned hard then I would bet it is already turning hard again. The bearings in the pulleys are sealed. Once they fail they cannot be repaired by oiling or spraying any type of lubricant on them. Replace that pulley and see if the problem still exists. Good luck.

 

ok thanks, but I still can't figure out the noise I know its on the pulley system somewhere but it just doesn't sound like a worn bearing

 

Did you spin the water pump, alternator, and power steering pulleys and see if they feel weird?

 

do you have a new/aftermarket/replacement/refurb'd alternator? they like to squeal at higher rpm's

oh and replace that idler before you get wd-40 on the belt and ruin it.

 

yea everything sounds and feels ok except the idler and tensioner but heres the twist on this whole situation when the truck is warm and making the noise around 2000rpm you can hear it the most inside the truck not under the hood where you think it would be. almost like its coming from the heater box. But when you take the belt off the noise goes away. NOW this is a far shot but i noticed that the fan clutch is staying engaged in the morning when the motor is cold and when it warms up the noise returns making me think it maybe a bad fan clutch that is making noise when warm and being transfered to the water pump through the shaft and the noise is then going through the coolant that is a good conductor of noise and i'm hearing it in the heater core, but it just seems to weird

thanks for all the help so far

 

clean5oh,

did you ever solve the noise problem? I recently bought a '97 that is making a very similar noise to what you've described. My noise only happens when there is no load on the engine though. When I press on the gas pedal the noise stops.
I am going to check the things the others suggested, just wondered if you were able to solve the issue.