3,000 miles into our trip. Stopped at a truckstop in Flagstaff, AZ for fuel. Is this squeaking noise a belt?
https://youtube.com/shorts/Lyn3S2XSRDo?feature=share
Sounds like a bearing in the automatic belt tensioner or a mis-aligned belt.
Old mechanic taught me this, take a 3 ft stick like a yard stick, lay one end on your ear, carefully touch the other end on/near bearings like alternator, power steering pump, tensioner, etc. Maybe hear the source of the squeak.
Pop the cover and see if you can determine which one is the culprit. I am pretty sure both tensioners are the same part #s. .
I just went through replacing it, pretty easy to change if you have a ratchet. Premature Hydraulic Belt Wear - Replace Tensioner (https://www.foreforums.com/index.php?topic=44239.msg447594#msg447594)
If they belt is misaligned, Pierce outlines how to check/fix.
You may not find the Gates part specifically, but this has a list of cross reference part numbers at the bottom that may allow you to find something local GATES-1999 8.3L ISC FREIGHTLINER TENSIONER-38504 (https://www.fleetpride.com/parts/cooling-system/belts-tensioners/heavy-duty-belt-tensioner/gates-heavy-duty-belt-tensioner-38504?cclcl=en_US)
Let us know how it goes.
A screw diver will work if you don't have a stick.
Just don't put the pointy end in your ear!
AC compressors can make a pretty good squeak. I had the clutch on ours make a squeaking noise I could hear up front at a stop light.
Loose belts on alternators, etc can squeak.
Pierce
Update: We drove another 150 miles and when we stopped for the night the squeaking was gone. Will check again in the morning. And we actually brought a stethoscope with us on this trip (why?) and maybe I'll try listening with that.
Did you drive through any dusty ground coming into the truck stop ?
That will make your belts squeal temporarily, usually means the pulleys are shiny so a shot of belt treatment will cure it.
Just a thought.
We have had a similar experience. Two years ago at MOT we had the coach serviced and then stayed on the property overnight. The next morning we had a loud squeak. The MOT service techs thought it was a belt, so they changed it. That did not fix it, so then they said it had something to do with the weather having turned colder. I don't remember what they claimed the weather affected, but the squeak went away after we drove it for a while. We have had the same thing one time since that we are aware of. It was also on a cold morning and went away when the engine and temperature both warmed up. We don't know for sure the cause of our squeak, but it sounds like it could be similar to yours.
I had a belt / pulley squeak the fist week home with my present coach. True it needed 2 idler"s which didn't stop the squeak. It didn't need the following water pump I replaced but it was easy and not expensive to replace. Still squeaked so replaced belts which still had life in them and still noisy. Ended up being dirt in the grooves on the crankshaft pulley. The hunt for a squeaky belt can take a while and if you parked it at a shop and told them to find it and fix it could be pricey so it's best if one can do the work themselves. Also true that cold weather can bring on a squeak that isn't there in warm weather. Of course one's main concern is a pulley bearing going bad and that can cause side of the road issues. Best not to be satisfied until squeak is identified and stopped, usually not a big deal, just wished I had wire brushed the crank pulley first. As it is I have good spare belts and water pump and as of today no squeak. Always good to keep a can of belt dressing and hit the belts with a bit a couple times a year. Brushing out grove"s on pulley is one more thing to check before buying un needed parts.
Is your belt tensioner bouncing? I am going to go with Brett. Been there done that with the U295 1997
Update: Haven't heard the squeaking since the day I originally posted, but I'll answer a few questions. It was a hot day and we'd been driving a couple of hours when I noticed the squeaking, so it does not seem to be related to cold belts or cold mornings. Also we had not recently been driving in any dusty conditions.
Currently boondocking in Kanab, UT for another week but when we start driving again I'll video the engine belts and tensioners. I will say the AC belt, the one up top without a tensioner, appears to flop around a lot and feels loose, but I don't know how it's supposed to feel, maybe that's normal.
The A/C compressor belt is adjusted by moving the compressor. It should neither "flop around" nor be bar tight.
A V belt should be tightened so midway between pulleys, you can just rotate it with your fingers 90° Too loose ruins the belt, too tight ruins the bearings.
Pierce
loose ac belt you mention will likely be your squeak, "flopping around" suggest it's beyond just a bit loose. Easy to tighten on that engine.
Update: I replaced the alternator serpentine belt with a new one, and also the belt tensioner. It was definitely bouncing and the local NAPA had both parts. Also tightened the A/C V-belt and picked up spare belts for everything. No more squeaks and away we go.