My 01 5.4 is making a noise like a noisy serpentine belt/ tensioner or power steering pump under the passenger side valve cover. I thought it WAS the belt or tensioner until I listened more closely and used a thesoscope. Sounds like a metallic whirring, spinning. Runs great, but don't know if it's a cam tensioner,or what. I don't hear it on the other side. Any ideas?

 

Figured the noise out today. It's the pcv valve. That little ball is going in and out like crazy, hence the noise. I'll replace it, I've never had one make that much noise. I assumed it would mostly stay open or closed , not in and out at hundreds of times a minute.

 

Mine is buzzing. I can pinch the hose and it stops but the engine idles down. It gets loud too. It is a motorcraft part but could be old. I'm going to change it out. My truck has a miss as well but doubt it is related.

 

Yep...I replaced the pcv today with a cheap Autozone one. Noise gone. That was a lot of racket that little baby was making.