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belt/pulley squeal that i cannot find... DRIVING ME CRAZY!!!

79K views 34 replies 13 participants last post by  Matt 6.0 
#1 ·
ok, so I've had this belt squeal for a while now and can't seem to pinpoint it. My belt was in poor shape so I started with that back in September. I don't drive the truck that often so I haven't put that many miles on since. The belt seemed to quiet it down some, but it is still there and becoming very noticeable again now. I never could pinpoint it exactly. I speculated the alternator or idler pulley...... tensioner pulley........ I dunno. I had the wife's stethascope out there trying to pinpoint it but I can't tell. It sounds like its coming from them all. Yesterday the alternator took a dump..... in the heart of the St. Louis blizzard... fixed and still squealing. Is there anything online showing all the pulley locations on the engine? When I look at the engine I see a grooved pulley on the tensioner and a smooth one. Also, on the engine I see a grooved idler on the driver's side of engine and a few other smooth pulleys. When I search online for parts they really only show 1 of the grooved type and 1 of smooth for my single alternator setup. When I look at engine I see more than that. Looking for a graphic or parts help. I'm thinking of replacing to cure squeal. Is there any 1 in particular on these trucks that are prone to squealing?

Any help is appreciated,
-Ryan
 
#4 ·
Ryan,
Help me with a better definition of the noise-- is it truely a squeal (like its slipping) or more of a chirp. If its high freqency enough, a chirp sounds like a squeal. If spraying the belt's rib surface with water clears it up, you have a misalignment issue where it enters/exits a grooved pulley. the misalignment could be angular or parallel, but most are angular unless a pulley was just reinstalled (like PS or vac pump).

I'd start with the pulleys in the belt path that are very close to each other. Look at tensioner arm misalignment, loose idlers, etc. The tensioner arm often misaligns as it wears.

If spraying the belt doesn't fix it, try to spray some wd on the bearings of each pulley. One of the bearings is getting tired. May take some time to locate it.

If you need any further assistance, let me know. My 25 yrs with Gates is happy to help...

Mike
 
#5 ·
ok thanks. I'll try that and let u know. i'll start with wetting the belt. to me it does sound like more of a chirp. to me it sounds like a bearing going out. just wondered if there was anything these trucks were prone for...???
 
#6 ·
we didn't do the program w/ navi and ford, but it does happen w/ specific models. Anytime you have real short belt spans, the sensitivity goes up. Something as simple as tolerance stack can do it on a specific unit.
 
#7 ·
u lost me there. but i'll try a few of those things and look to see if its misaligned or something. to me it really sounds like a bearing going out. like I said before, the parts houses only call for 2 different ones (smooth & grooved) but I sure see a few extra on the truck....??? the chirp or squeal does get louder/more frequent as rpm increases.
 
#8 ·
Here's our parts;

Serpentine; W/Single Alt.; W/O F53 Stripped Chassis
Automotive V-Ribbed Belt (Heavy Duty) K081265HD
Automotive V-Ribbed Belt (Standard) K081265
Serpentine; W/Dual Alts.; W/O F53 Stripped Chassis
Automotive V-Ribbed Belt (Heavy Duty) K081325HD
Automotive V-Ribbed Belt (Standard) K081325
Serpentine - Alt.; W/Dual Alts.; W/O F53 Stripped Chassis
Automotive V-Ribbed Belt (Heavy Duty) K060658HD
Automotive V-Ribbed Belt (Standard) K060658
Serpentine; W/F53 Stripped Chassis
Automotive V-Ribbed Belt (Heavy Duty) K081331HD
Automotive V-Ribbed Belt (Standard) K081331
Tensioner Assy. - Alt.; W/Dual Alts.
Belt Drive Tensioner 38321
Tensioner Assy. - Accessory Drive
Belt Drive Tensioner 38257
Idler Pulley - Smooth; W/A.C.
Belt Drive Pulley 36234


The belt on the top of the list and the bottom two #s are what you likely need to look at. We recommend replacement of the tensioner as a whole unit as well as the pulley. You 'can' replace bearings but they need to be in perfect alignment to not affect the pulley's alignment when reinstalled.
 
#10 ·
Let me ask a question here, does it "chirp" while the truck is running or just when you start it up and shut it down?
 
#12 ·
subscribing.... mine chirps at idle.... its very annoying..... sometimes it has a rattle along with the chirp
 
#13 ·
I'm subscribing too mine also has an annoying chirp squeel when running but I've replaced several pulleys on it already so I'm curios as to what yours ends up being. Has anyone's stock belt that came on the truck been so tight that it can't be put back on once taken off? I took my stock one off a while back cause I had the tentioner pulley bearing go bad and the stock belt would not go on was an inch or more to short? Just asking no big deal.
Also has the chirp at start and stop engine so what does the chirp at start and stop mean?
Just thinking maybe I can get some other stuff taken care of on it while its down waiting on a ficm
 
#14 ·
I installed a new belt, and two new idler pullies the first time I rebuilt my engine.
Then after awhile, something was squeaking again.

I put up with it for 2 years...it just squeaked all the time...but here's the thing...compared to the rpm's of the pulleys, (Alternator, P.S, A/C, idler pullies, etc.) it was too slow to be one of them...so I thought it may have been the belt tensioner itself, so I pulled it off, and worked on it in the vise. Squirting "Kroil" inside of it, and working it back and forth.
Put it back on, and the squeak continued on...

Bought another new belt for $55.00 bucks, put it on, no more squeak!!!

I had over 180,000km's on the first belt, and the second belt only had maybe 20,000km's. (And it was NEVER exposed to mud.)

I would try another belt if I were you.
 
#16 ·
On a cold start or just sitting for a extended period of time my belt squeaks. Once it runs for a few minutes it goes away and when I shut it off it squeaks again.
I think I just need a new belt and it will stop.
 
#17 ·
mine squeals all the time. not just a start up or shut down squeal. and definitely gets louder and more frequent as rpm is increased. The belt is not but a few months old and only has a few thousand miles on it at best. I guess I could do another belt on there but i'm doubting that'll help because when I put this belt on it the squeal quieted some but never did go away. I dunno...... I suppose i'll start throwing parts at it once the weather warms a little.
 
#18 ·
I know this is going to sound really crazy but, mine would chirp when i shut it off or started it. Started turning my a/c or heat completely off before i turned the truck off, no more chirp when i shut it off or turn it on. Tried it again with the air on, and it chirped. I know it sounds crazy but if you turn your heat or air off before you shut the truck down, it helps. Something about the compressor isnt binding or working against itself.
 
#19 ·
Squeaking on shutdown is an annoyance that is encountered with many diesel engines. At idle rpm and below the torsional inputs are very high and the tensioner arm has to have a lot of leverage on the belt to maintain necessary tension--when it doesn't, the belt briefly slips. Many heavy truck engines have specific logic written into the tuning and will make sure that the fan clutch is engaged to take extra load off the motor.

As I said earlier, the chirping issue is a different issue. This is a belt/pulley groove fit issue-- all belt mfgrs profile their belts differently so in the right environment, some can chirp and some dont simply based on the material and profile differences. A belt swap can stop the noise. However, the noise may come back--there are chronic chirp issues that occur due to misalignment of the pulleys. This causes a deformation of the belt 'v' over time and eventually the belt chirps. This is a drive issue caused by tolerance stack/pulley location, tensioner failure, etc that may or may not be easily corrected.

First thing, first-- isolate the belt/pulley fit issue by spraying water on the belt. If the noise goes away, you have a belt/alignment issue. If noise stays, you have a drive component issue (pulley, bearing, accy, etc).
 
#21 ·
They have TSB's from Ford on this subject....The Early models they had one to replace the Water Pump Pulley and Serp. Belt....I can't find that one....here's one for the late models.


The TSB is 07-26-1

2006-2007 F-Super Duty


ISSUE:
Some 2006-2007 F-Super Duty vehicles equipped with a 6.0L engine and built between 1/1/2006 - 8/31/2006, may exhibit a belt chirp noise on cold start.

ACTION:
Follow the Service Procedure steps to correct the condition.

SERVICE PROCEDURE

1. With tires straight ahead and no steering or brake input, start the truck and listen for belt chirp.

2. Press the brake pedal and listen if the noise goes away.
a. If the chirp noise goes away with brake input, proceed to Step 3.
b. If the chirp noise does not go away when the brake is applied, do not continue with this TSB, follow front end accessory drive (FEAD) noise diagnostics in the Symptom Chart per the Workshop Manual, Section 303-05.

3. Replace the Main Drive Belt and the Power Steering Pump and Pulley Assembly per Workshop Manual (WSM), Section 211-02.

PART NUMBER PART NAME
6C3Z-3A696-C Pump And Pulley Asy
3C3Z-8620-BC Belt - Dual Alternator
3C3Z-8620-DB Belt - Single alternator

WARRANTY STATUS:
Eligible Under Provisions Of New Vehicle Limited Warranty Coverage
IMPORTANT: Warranty coverage limits/policies are not altered by a TSB. Warranty coverage limits are determined by the identified causal part.

OPERATION
072601A

DESCRIPTION
2006-2007 F-Super Duty 6.0L Built From 1/1/2006 To 8/31/2006: Replace The Power Steering Pump And The Main Drive Belt, Includes Time To Remove And Install Radiator, Fan Drive Clutch, Fan Shroud (Do Not Use With 3674A, 8620F, 8005A, 8616A, 3733A, 8146A)

TIME 2.0 Hrs.


DEALER CODING
BASIC PART NO. CONDITION CODE
3A696 42
 
#22 ·
I put some irish spring bar soap on the belt and the squeak went away immediately. after a few minutes of running it came back but that did shut it up. So I'm assuming i do not have a bearing going out but could still possibly have a pulley issue............??????? I mean this belt is extremely new, so i dunno really........ I guess I need to look into that other TSB also.
 
#23 ·
Yes, its likely a belt/pulley interface issue, not a bearing issue. Could be related to, a) the specific belt construction you currently have and possible pulley 'misfit' or, b) a specific misalignment somewhere in the drive system.

I don't have a pic or layout of the 6.0 set up, but if has a area around the tensioner where there are short belt spans between pulleys, I'd look at any misalignment in that area. Start with the tensioner's arm to cup alignment(you should remove belt and rock the tensioner back/forth and fore/aft looking for excess movement). If the tensioner has 100K+ on it, its definitely on its way out.

The new Gates Fleet Runner belt is compounded w/ EPDM rubber which is unlike any other replacement belt in the aftermarket they are all chloroprene). Its more money, but worth a try if nothing else mechanical shows up.
 
#24 ·
I just went out for dinner and was driving the truck and the squeal got SUPER loud upon acceleration! Like people were looking around and at me like, "who's P.O.S. is that making that noise" LOL!!! so when I got home i popped hood and observed a few things: the tensioner arm was fluctuating a little bit as it ran which I thought odd, and also the noise sounded very much like it was coming from the grooved pulley on the tensioner assy. So I'm brainstorming a little and thinking that maybe the tensioner is weak and maybe has enough tension to hold belt on but weak enough to allow belt to slip or something upon acceleration????? Possible???? Or the grooved pulley I described is F'd up like said before...??? I'll probably pull belt off tomorrow and inspect a few pulleys. Thinking about R&R the tensioner assy for good measure???? I dunno if it should move/fluctuate when running or not.....
 
#25 ·
if ya rubbed enough irish spring on it, the coef of friction went in the toilet and it slipped... factory tensioners were bought on price, if its got 100k on it, it should be replaced.
 
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