$#^%#$%&*$ Accessory drive pulley

[jmiller]

Stated to hear a clanking sound at idle in the truck. It was louder with the A/C on, quieted down when it was idled up.

A/C compressor pulley was loose and sounded rough,so it got replaced. The noise was better, but still there.

I was able to turn the alternator pulley 1/3 to almost 1/2 turn by hand. The crank drive pulley elastomer had sheared. :mad5:



The pulley only had 20K miles on it. I was pissssssed.


Installed the new one, every thing is good now.

 

[iamdave0887]

Made in China junk is what it boils down to.

 

[jmiller]

True

 

[iamdave0887]

That's one reason i'm glad my K-5 has a solid pulley. No rubber to fail, but the belts do jump around a bit due to the lack of vibration dampening the rubber in the pulley provides. The rubber dampened crank pulleys came about in ~86 due to the A/C v-belt jumping around so much that it actually would hit the bottom of the upper rad hose where it attached to the t-stat housing and eat right through it. GM made a special clamp with a guard as a band-aid, which worked very well(i still have mine in service), but the rubber dampened pulley was the final solution to the jumping V-belts.

The 6.5 just got the "upgrade" of the rubber dampened pulley right from the start since GM was already making them for the serp belt 6.2s.

 

[midniteplowboyy]

Atleast it was the rubber that broke, and not the four spokes that center it. I've got atleast ten of them in the scrap pile that the rubber let loose, atleast there easy to change. The four spokes broke(rubber still good) on my 93 taking the end of the crank with it. Damn china junk.

 

[Acesneights1]

That's one reason i'm glad my K-5 has a solid pulley. No rubber to fail, but the belts do jump around a bit due to the lack of vibration dampening the rubber in the pulley provides. The rubber dampened crank pulleys came about in ~86 due to the A/C v-belt jumping around so much that it actually would hit the bottom of the upper rad hose where it attached to the t-stat housing and eat right through it. GM made a special clamp with a guard as a band-aid, which worked very well(i still have mine in service), but the rubber dampened pulley was the final solution to the jumping V-belts.

The 6.5 just got the "upgrade" of the rubber dampened pulley right from the start since GM was already making them for the serp belt 6.2s.

A little known fact too is that when Gates discontinued "8" series belts the problems started for 6.2s. The supposed "beefed" up "7" series is too narrow which is a major contributiing factor to why 6.2's burn up alt belts.

 

[iamdave0887]

A little known fact too is that when Gates discontinued "8" series belts the problems started for 6.2s. The supposed "beefed" up "7" series is too narrow which is a major contributiing factor to why 6.2's burn up alt belts.

There's a special belt adapted from a HD truck for the 6.2 alt belts. Belt number 5725 IIRC. I have the numbers to the belts in my wallet. Going to get another set. The A/C belt on the truck is wrong, and is starting to stretch out to the point of no return. Gates or not, the wrong belt, is the wrong belt.

 

[Missy Good Wench]

Best thing to do on these older 6.2 engines is to scare up a complete serp drive and be done with the V belt issues.

The China dampened pulley, even the serp ones are junk though.

Missy

 

[bk95td]

A bad belt tensioner can take out the rubber in the pulley also while it is eating the bearings out of all the accessories.
My olds 5.7 diesels had the lower hose clamp with a shield.