squeal at startup

[john cris]

Hey,
Not that this issue hasn't been pounded to death but I need help from those who have fixed this. I have an 03' Explorer 4.0 V6 sohc. It has for a long time been making a squealing noise on start up that is very similar to belt squeal. I figured this is a no brainer so I replaced the belt, idler pulley and tensioner with motorcraft parts from the stealer. Problem still there. So I remove belt and check all accessories for bearing issues. I detect the smallest bit of noise from the forward bearing on the alternator so I replace the alternator. Problem still there. I remove belt again and re-inspect all accessories for any previously undetected issues. Nothing is misaligned or tight or rough in any way. That includes the water pump, power steering pump, a/c compressor, fan clutch and vibration damper. The damper looks normal, ie: not separated. I marked it to check for possible slippage and found none. I've read more on this subject online than i care to admit. I'm a capable mechanic and take care of my own stuff. I pulled the cam sensor and inspected hoping to find a synchronizer below it but there isn't one in this motor. This motor has about 140k on it, runs smooth and gets decent gas mileage. I read that the timing components on this motor can be problematic due to chain guide wear. I need to eliminate all possibilities before opening up the front of the motor. What am i missing?
Thanks,
John

 

[john cris]

Resolution

Well the squealing belt issue is gone. After replacing the tensioner, idled pulley, belt 3 times, and harmonic balancer it turns out it was the belt all along. Back in the day we used to use shorter or longer Vee belts as needed to get the right tension and reduce squeal. I should have remembered that with this serpentine belt. Ended up going with a shorter belt to put the tensioner more in the middle of its travel range and boom no more squeal. Felt like a dummy for not trying this sooner. Guess I figured I'd just use stock parts and that would take care of it. The fix seems completely logical now but damned if it eluded me till I spent too much fixing it. So the lesson here is keep it simple stupid! Gotta say the solution emerged from a conversation with a local parts guy. Sometimes just hashing it over with someone who has been there is invaluable.
So there you go. From now on I'll try not to overthink the hell out of it. Yeah right!
On to the next issue, lol
John

 

[imp]

Well the squealing belt issue is gone. After replacing the tensioner, idled pulley, belt 3 times, and harmonic balancer it turns out it was the belt all along. Back in the day we used to use shorter or longer Vee belts as needed to get the right tension and reduce squeal. I should have remembered that with this serpentine belt. Ended up going with a shorter belt to put the tensioner more in the middle of its travel range and boom no more squeal. Felt like a dummy for not trying this sooner. Guess I figured I'd just use stock parts and that would take care of it. The fix seems completely logical now but damned if it eluded me till I spent too much fixing it. So the lesson here is keep it simple stupid! Gotta say the solution emerged from a conversation with a local parts guy. Sometimes just hashing it over with someone who has been there is invaluable.
So there you go. From now on I'll try not to overthink the hell out of it. Yeah right!
On to the next issue, lol
John

Thank you for taking the time to inform, despite lack of quick answers. I would have wondered all night long.....imp

 

[TechGuru]

I use nothing but GoodYear GatorBack (now called Continental Elite) belts in the OEM specified size on all of my vehicles and have never had any problems.

http://www.rockauto.com/en/moreinfo.php?pk=1332875



Many many years ago had brand new OEM size Gates Micro-V squeal like crazy.

 

[john cris]

Napa didn't have a Gates belt so I went for their micro vee house brand. For now it's quiet, and if that SOB even makes so much as a tiny squeak I'm launching i into the lake. haha Thanks for the tip though.
John

 

[swshawaii]

Napa didn't have a Gates belt so I went for their micro vee house brand. For now it's quiet, and if that SOB even makes so much as a tiny squeak I'm launching i into the lake. haha Thanks for the tip though.
John

NAPA belt IS a Gates Micro-V, even has the same part number (060854) and specs. Great belt for me, and silent.

http://www.napaonline.com/napa/en/p/NBG25060854/NBG25060854_0261342843

http://www.rockauto.com/en/moreinfo.php?pk=4289&cc=1414493&jsn=435

 

[john cris]

Yup,
That's the belt I got. It's been great
John

 

[TechGuru]

NAPA belt IS a Gates Micro-V, even has the same part number (060854) and specs. Great belt for me, and silent.

http://www.napaonline.com/napa/en/p/NBG25060854/NBG25060854_0261342843

http://www.rockauto.com/en/moreinfo.php?pk=4289&cc=1414493&jsn=435

Like I said, squealed out of the box for me. but this was on a GM vehicle many years ago...

 

[TechGuru]

Yup,
That's the belt I got. It's been great
John

But you bought one a size or two smaller right?

 

[john cris]

That's right. It was 1" shorter which put it right in the middle of the range of the tensioner. I'll post the Napa part number later this morning
John

 

[TechGuru]

That's right. It was 1" shorter which put it right in the middle of the range of the tensioner. I'll post the Napa part number later this morning
John

The thing is you should not have needed to do that.

Are all of your pulleys the correct size? Some people install smaller crank pulleys to free up very little horsepower.

 

[john cris]

Yes I agree that should not have been necessary. The entire motor is stock as is the chassis . The Napa belt is p/n 060864. The Motorcraft belt p/n is 7L5E 8620.
The tensioner is a Motorcraft. All the pulleys are stock. So I'm unsure why this has happened. Maybe the previous owner changed something that is not apparent .
I doubt it though as everything looks stock. I would like to know why as well but have other gremlins to chase. Thanks for your insight though.
John

 

[swshawaii]

Shorter belt is also a known noise fix on stock ST's using the OEM length belt.
Stock length tensioner position top pic vs. 6/10" shorter belt. (Gates K060860)

http://www.mysporttrac.com/shared/msgboard9e.asp?BOARDNAME=MSG&VIEW=1313192

http://mysporttrac.com/shared/msgboard9e.asp?BOARDNAME=MSG&VIEW=1300307

http://mysporttrac.com/shared/msgboard9e.asp?BOARDNAME=MSG&VIEW=1162118&sitename=mysporttrac

 

[john cris]