Weird Noise Between 1600 and 2100 When Cold (1 Viewer)

[jahawk]

About a month ago my fan bearing let loose on a trip. I obviously replaced it as well as the tensioner pulley, and idler pulley. Put everything back together using a fan and clutch I borrowed from a fellow club member. After this I drove the truck on about a 400 mile trip with no issues. When I get back I pulled of the borrowed fan and clutch and threw on my old clutch with a new Aisin fan. Now a have this noise that sounds almost like the belt slipping between roughly 1600-2100 when cold. When the truck warms up its gone.

I've thrown on a new belt since then with no difference. Has any one ever had a fan clutch make that noise? A fan? I'm at wits end here.

I've used a stethoscope and the noise isn't coming from the alternator or PS pump (which is new).

All help is appreciated before I burn this LX to the ground.

Jim

 

[carskie]

Any follow up on this? I have a 99 LC making this same belt slip/whooooop noise typically when cold, only at 1800-2200 rpm.
Hard to stick the stethoscope near the fan & clutch area at rpm. No obvious noises from other items on the serpentine belt.
I could post an audio clip if that helps.

John

 

[jahawk]

Any follow up on this? I have a 99 LC making this same belt slip/whooooop noise typically when cold, only at 1800-2200 rpm.
Hard to stick the stethoscope near the fan & clutch area at rpm. No obvious noises from other items on the serpentine belt.
I could post an audio clip if that helps.

John

Yep, it was the fan clutch.

Jim

 

[carskie]

Thanks, I'll focus there.