Good Morning,
I have a 2002 F250 7.3L Crew cab short bed with 139,XXX miles on it. About a month ago it began making a chirp / squeak sound under the hood. I parked it and scheduled it to go to my local diesel mechanic. They weren't able to get me in for a few days so I drove my dad's truck. The day before I was to take it in, I drove it to let my dad hear the sound and of course it stopped. I have driven it for the month since then with no issues, even towing my 8000# travel trailer 500 miles round trip in the mountains for a weekend getaway with the family. On my way to work this morning it began again. I have read numerous threads about belts, pulleys, tensioners, etc. but they seemed to have a constant sound. My sound is not rhythmic but intermittent. It is also accompanied by some light rattle sound which I can feel under my left foot. It does it when idle or under power but still there is no constant rhythm to it like I believe you would get with a belt whine. This mornings conditions are as such: 55 degrees and rainy out. The first time it happened it was 50 degrees but dry. There have been colder and wet days in between these two instances with no noises. My first thought is that the belt might be slipping. Any help is appreciated.

 

Hard for the serpentine belt to slip. If it's not rhythmic, another common chirp/squeak that you can feel under your feet is the front swaybar bushings, especially the pressed-in bushings on the endlinks. How do they look?

The springpacks themselves can wear through the plastic pads on the ends, making a squeak, but usually you just hear that, with no rattle in the floor.

 

The sound still occurs sitting and idling so I don't think that is it.

 

My wife's truck would make a chirping/squeaking sound when first started on the cooler days. I initially thought it might be the bearings on the tensioner assembly and idler pulleys so I change them out. It worked for a while but the sound came back after a little while so I investigated a little further.

In my case it turned out to be a bad tensioner assembly. I changed that thing out and the chirp has not returned.

 

That does sound reasonable - I was watching mine, and it doesnt move rythmicly, but seems to have a random movement.

It will be interesting to see what you find, Chris.

 

Antifreeze on Surpentine (spelling???) belt will cause a chirp or squeak...
Don't ask me how I know this!!!!!!!

 

I don't think it is the antifreeze on the belt issue. I have dealt with that before and this is nothing like that. Does not make the sound at idle. It's only when I get over about 15 miles an hour. It is a loud noise like a squeaking trailer sounds actually.

 

https://www.ford-trucks.com/forums/1...of-engine.html

 

Chris, earlier in this thread you said the noise also happens sitting and idling. I'm confused. When is the noise the worst? Maybe we focus there.

 

I didn't mean to say while idling. It happens when I get over 15 miles an hour even if I'm pushing on the gas or if my foot is off of the gas. I have changed out the belt and tensioner assembly and that has not fixed the problem.

 

Ok, so if you're moving above 15mph, tell us about the swaybar bushings, endlinks. How do they look? Can you wiggle them or see deterioration of the bushings? This is the common failure if you can feel the rattle under your feet while moving.

 

All of those items are fine. It is something under the hood.

 

I replaced the tensioner and belt. No luck on the sound. I removed the water pump and as I am going to reinstall it I notice the rubber on the harmonic balancer is bulging out some and looks pretty ragged. What are my options at this point? Is this something a weekender like me can do? Is there a video for this somewhere?

 

https://www.ford-trucks.com/forums/1...ced-video.html