I recently purchased a 2001 F150 4.6L V-8. The truck has 78K miles on and runs good except an annoying whine. I've heard it described as sounding like a super charger. It is constant, at idle or acceleration. I replaced the idler pulley because it was scuffed up but the whine persisted. I took the belt, which looks fine, completely off and the noise went away.

I checked all of the pulleys and they all rotate except for the bottom middle one, the crank shaft pulley. Should this pulley rotate by hand and if so can I replace this pulley? It is rusted pretty bad. If it's not this, any other ideas?

Thanks - Trevor

 

Any suggestions?

 

well if it sounds like a supercharger, and not a belt whine, it sounds like it would be your powersteering pump. When those start going bad they sound like a supercharger, dont ask me why lol. I would start there, but thats what it sounds like to me.

 

To answer your question regarding the crank pulley: If you can turn this one by hand easily you have a real problem. This pulley is driven by the engine directly off the crankshaft(and pistons, etc) and drives the belt.

 

you can replace the bearings in both idler pulleys, as well as the tensioner. It's not to expensive.

 

Thanks for the information. I'll replace the power steering pump and maybe the hoses and pulley this week and post my results.

 

Well it was the power steering pump making that awful whine and it's gone now. I spent about $45 for the pump and fluid. The first time I pulled and replaced it it took me about 4 hours! I had to do it again because I couldn't get the pulley back on but the second time was much quicker, just over an hour. Sound is completely gone though so thanks for the advice.