I have a 1992 F-150 with about 187K miles and the 5.0 V8 engine and an automatic transmission. The truck is not driven very much. To give you an idea, I filled up both gas tanks on Christmas day 2014 and didn't put gas in it again until May. And it's not because it gets 250MPG!

The last few times I used it, there has been a very loud squeaking noise coming from the engine.

Here is a link to YouTube video:
In this video the A/C is switched off. The compressor is dying and does make some noise when the clutch is engaged, so I made sure it was off when I shot the video. The noise changes in pitch with engine speed.

The truck has a new alternator that was replaced about 250 miles ago along with the serpentine belt and tensioner pulley. The squeak started sometime after that.

In an effort to isolate the noise, I removed the belt and spun each engine accessory using a drill and an extra serpentine belt. This was inconclusive, and after I put the belt back on, the squeak was gone! But it came back within a few miles.

It sounds like it coming from the passenger side of the engine, but I can't tell for sure. I used a mechanic's stethoscope on each of the accessories and that was also inconclusive.

By any chance is this a common issue with a documented fix?

 

Sometimes the cheaper belts squeal. Spray some belt dressing on it to see if it stops. Spray some wd40 on back of tensioner pulley to see if it stops. After that I'd be looking at the alternator bearing being bad...just because they're new doesn't mean they're good.

 

I had the same problem on and off for a long time. After many belts and new Dayco tensioners I finally bought a Gates tensioner, pulley and belt. Problem gone . Been more than a year now.

 

This isn't intermittent - it does it all the time. It's very annoying!

 

I know it's all the time. I just bought better parts and no more problems.

 

Were you hearing a noise similar to what I am? It doesn't sound to me like belt squeal, but I'd be willing to try a higher quality belt and pulley to see if it helps. I can at least eliminate that as a variable...

 

Yep, same sound. Also make sure all your pulleys are lined up. Make sure your belt is running straight. Good luck, I fought my problem a long time.

 

Hmmmmm. I really hope I don't have to start throwing a ton of parts at this thing. Is there a trick to making sure all the pulleys are aligned?

 

Here's a simple way to find out if it's belts, pulleys or if it's internal. Remove the sepentine belt and start the truck.

 

Mike1: I did that. Quiet as a church mouse with no belt. So it's definitely the belt or one of the accessories.

 

Sounds like the alternator bearing is bad.

 

Sounds like a bearing.

I'm surprised the stethoscope didn't reveal the noisy culprit.

I would pull the alternator and check the bearing myself.