6.4l Serpentine belt chirp noise fix

makuloco2000

Full Access Member
Joined
May 13, 2008
Messages
99
Reaction score
0
Location
USA
One of my best repair videos. Here is the most common concern I see and the REAL fix, there is a tsb from ford on changing idler pullies, I have never seen that work. New belt and tensioner fixes them everytime. The other thing that sounds like a belt chirp on these unfortunately is the roller lifters failing as the need bearings give out. Let's hope your truck doesn't have that issue and this is it. Hope this helps!

http://www.youtube.com/watch?v=pr6s-vnYDoU
 

WANTED

SDD Junior Member
Joined
Jan 3, 2013
Messages
29
Reaction score
0
Location
Colorado
Ever hear of the fan clutch being the culprit? I have a periodic squealing that that I've sourced to that general area. I've already replaced both belts and tensioners.
 

makuloco2000

Full Access Member
Joined
May 13, 2008
Messages
99
Reaction score
0
Location
USA
Ever hear of the fan clutch being the culprit? I have a periodic squealing that that I've sourced to that general area. I've already replaced both belts and tensioners.

You sure its not the roller lifters? The cam is in that general area. I have not hear of a chirp being caused by the fan pulley not on a 6.4l anyway. There would have to be a decent wobble. While the belts were off did you check the pulled for grinding and excessive play? If it is happening from that general area and you catch it spray some water on that area with a sprayer bottle. If noise goes away we know its a belt/ pulley issue. Then go from there.
 

ajvolpe

SDD Junior Member
Joined
Mar 7, 2009
Messages
7
Reaction score
0
Location
Viera FL
I had Ford replace my idler pulley approximately 2 years ago under the tsb. The chirping noise continued, but not as much. It only occurs when it is reasonably cold outside, and goes away after a short warm up. A new belt and tensioner might be the answer, but at what cost.
 

WANTED

SDD Junior Member
Joined
Jan 3, 2013
Messages
29
Reaction score
0
Location
Colorado
I personally replaced both tensioners and belts. I still get the squealing or chirping. Always happens when it's cold but does eventually go away. I occasionally get it on and off again on long road trips. Hit or miss if it it occurs while driving around town.

I tried the water trick to no avail. I did notice the accessory tensioner getting slightly cockeyed so I replaced it and the belts, as I'm at 85k which is close enough to justify swapping the belts and tensioners.

As far as the squealing, it is loudest right at the fan area. It doesn't always happen when the fan kicks on. The only other thing I can think of in that general area is the ac compressor.

Otherwise, How can I narrow down if it is the roller lifters? I would think it would be a more constant chirping or squealing if it was, right?
 

BIG JOE

Full Access Member
Joined
Apr 6, 2005
Messages
5,423
Reaction score
55
Location
CenCal
Engine off.

Rub a bar of >>[Ivory Soap]<< on the ribs of the belt, on the few places you can reach.

('ol guy stuff.... from " Back In The day ". ;):D:dunno)

Joe
 

makuloco2000

Full Access Member
Joined
May 13, 2008
Messages
99
Reaction score
0
Location
USA
I had Ford replace my idler pulley approximately 2 years ago under the tsb. The chirping noise continued, but not as much. It only occurs when it is reasonably cold outside, and goes away after a short warm up. A new belt and tensioner might be the answer, but at what cost.

As stated the tsb with the new idler and belt hardly fixes the issue put a good flashlight down in there and check for that cocked belt tensioner where the belt is not riding in the exact center tensioner pulley.
 

makuloco2000

Full Access Member
Joined
May 13, 2008
Messages
99
Reaction score
0
Location
USA
I personally replaced both tensioners and belts. I still get the squealing or chirping. Always happens when it's cold but does eventually go away. I occasionally get it on and off again on long road trips. Hit or miss if it it occurs while driving around town.

I tried the water trick to no avail. I did notice the accessory tensioner getting slightly cockeyed so I replaced it and the belts, as I'm at 85k which is close enough to justify swapping the belts and tensioners.

As far as the squealing, it is loudest right at the fan area. It doesn't always happen when the fan kicks on. The only other thing I can think of in that general area is the ac compressor.

Otherwise, How can I narrow down if it is the roller lifters? I would think it would be a more constant chirping or squealing if it was, right?

The roller lifter noise generally happens when hot, so hopefully that is not your noise. Since the fan is so large on the diesel engines, I generally uses a garden hose on the belt engine running to get enough water in there, the fan kinda blows away the spray bottle stuff. Sorry bout that. The positive way we check for the source of the noise is to run the engine with the belt off. If it consistently happens on a cold morning start I would say pull belt and let sit outside overnight for a start up in the am, leave ac belt on as the ac compressor is very unlikely. The noise happens on smooth pulleys. Before all of this try the water trick with hose as stated, then get a good flashlight and check for any pulleys that seem to have a wobble to them, some will have a slight wobble idlers are the worst for this even new. Check the belt as it goes over these pullies the the belt track straight or does it track from side to side. Again also did you check the pulleys when the belts where off? Is yours the early 08 6.4l where the idler pulley tsb might apply. Also just an FYI. Ford went through several belt material changes on the 6.4l trying to get rid of the noise on some pesky engines. I have put on the old "revised belt" and the newest "revised belt" they are a night and day difference in design. Something to think about, ford didn't go through that much trouble and money designing a new belt because they didn't have a problem child on their hands. Just some things to check. I like big joes idea also, at least for a diagnosis tool.
 
Last edited:

WANTED

SDD Junior Member
Joined
Jan 3, 2013
Messages
29
Reaction score
0
Location
Colorado
The roller lifter noise generally happens when hot, so hopefully that is not your noise.

Would it be a constant squealing if it was when the motor is hot, or would it periodically come and go? The only other condition under which it happens is when the truck is under acceleration when it does occur. If I increase acceleration for a bit, I can get it to go away. I have no reference for what a needle bearing failure sounds like. If you have a link to a youtube recording somewhere, I could give you a better comparison to mine.


Since the fan is so large on the diesel engines, I generally uses a garden hose on the belt engine running to get enough water in there, the fan kinda blows away the spray bottle stuff. Sorry bout that. The positive way we check for the source of the noise is to run the engine with the belt off. If it consistently happens on a cold morning start I would say pull belt and let sit outside overnight for a start up in the am, leave ac belt on as the ac compressor is very unlikely. The noise happens on smooth pulleys. Before all of this try the water trick with hose as stated, then get a good flashlight and check for any pulleys that seem to have a wobble to them, some will have a slight wobble idlers are the worst for this even new. Check the belt as it goes over these pullies the the belt track straight or does it track from side to side. Again also did you check the pulleys when the belts where off? Is yours the early 08 6.4l where the idler pulley tsb might apply.

I'll give the garden hose method a try. I did check the pulleys when the belt was off and found nothing the seemed out of the ordinary, nor found any binding. I may just say the hell with it and replace all the pulleys. The belts fit perfectly over everything and exhibit not odd movement when the truck is running at idle. The noise got better when I replace the belts and tensioners. The TSB may in fact be the culprit and what I perceived to be within the norm of tolerance may in fact be off.

Also just an FYI. Ford went through several belt material changes on the 6.4l trying to get rid of the noise on some pesky engines. I have put on the old "revised belt" and the newest "revised belt" they are a night and day difference in design. Something to think about, ford didn't go through that much trouble and money designing a new belt because they didn't have a problem child on their hands. Just some things to check.

I'm curious as to what they revised to. Is it kevlar or something else? Any pictures of the differences?

I like big joes idea also, at least for a diagnosis tool.

This one is definitely one of my trickier squeals to diagnose. Pinpointing it has been a pain in my ass. This noise is less troubling and more annoying if anything.
 

Members online

No members online now.

Forum statistics

Threads
30,506
Messages
266,043
Members
14,622
Latest member
rhensonsr
Top