First post: Advice needed on 98 6.5 4 wife: what of shreading belts?

[BlueSky94]

I just subscribed to this site in hopes that it has the same level of comradery that the cummins turbodiesleregister.com site has.

I am getting ready pick up a 98 3/4 ton LT subburban with the 6.5 td. Truck has 120 miles and appears in excellent shape and has been maintained by the local dealer.

What are the trouble spots that I should watch out for? I notice a little oil around the turbo and from what looks like to the the oil filter (drips onto the front differential).

Truck starts drives flawlessly but current owner states its stumped the dealer as he shreds the serpantine belt withing 6 months..what is this issue? Would it be just the tensioner bearing slipping? I looked VERY closely at this and 1) the belt is shreded any about to break and 2) I could not see anywhere that this would be making contact and everything in lined up. HELP! Is this an indication of a more serious issue?

The only issue I know of with the 6.5 is the FSD. Please advise as to other know problems or items that I should look at. The is a pretty sizeable purchase for our family and we really don't wont to be burned.

Thanks in advance to all who can and will offer their expertise ad advise.

[HowieE]

One thing you might look at as far as belt shreding in the harminic balancer on the end of the crankshaft. These balancers are made up of an inner and outer metal ring and joined by rubber. If you look in from under the truck at the back side of the balancer you will see this rubber ring between the to metal rings. If the ring shows any sign of cracking or entending, tearing, out of it mounting place it could be wabbling enough to give problems in the belt.
Any of the bearing points along the belt also could be causing strain on the belt if they have excessive drag, AC compressor, alternater, tensioner,

[HowieE]

One thing you might look at as far as belt shreding in the harminic balancer on the end of the crankshaft. These balancers are made up of an inner and outer metal ring and joined by rubber. If you look in from under the truck at the back side of the balancer you will see this rubber ring between the to metal rings. If the ring shows any sign of cracking or entending, tearing, out of it mounting place it could be wabbling enough to give problems in the belt.
Any of the bearing points along the belt also could be causing strain on the belt if they have excessive drag, AC compressor, alternater, tensioner,
The oil leak on the front differential is most likely the oil cooling lines that lead to the cooler forward of the radiator. These are notorious for leaking. Do Not replace them with GM parts as they will just leak again.

[rjwest]

I have had belt shredding.

1. I would reccomend the GM tensioner asm.
It will have a lip on the pully.
comes as a complete unit, tensioner and pully.

2. GM belts, aftermarket strech and jump/shreed.

3. check all other pullys, also make sure
soneone has not put on a alt/compressr with wrong
number of groves.

4. An as Howie stated , checkm the Crank pully.

[BlueSky94]

I had a itsubitchy 4x4 years ago that stung me when the mechanic cross threaded the crank pully after doing a timing belt change....20k later, I was looking at a new crank....

How bid of a deal is the crank pully issue you are describing? I'll have to instpect this for sure but still looking to leverage any experience out there. -thanks

[HowieE]

The crank pulley is one of those things that either fails or it doesn't fail. My old 6.2 has 235,000 miles on the original but some go in lees than 100,000. You just have to check it when you change the oil.

[HowieE]

I posted too soon above.
The pulley damper is designed to absorb some of the internal shocks of the engine. I assume depending on the quality of the internal balancing of a given engine will effect the life of the damper.

[catmandoo]

the crank pulley is easy to check,it has 4 bars set up in an x patten between the center hub and the outer belt surface,it's held in place with 4 bolts which should be centered between these bars,if they are off to one side or the other it's slipped and has to go ,now.my old 94 sub developed a wierd vib one day and just by coincidence that night on this site there was talk of this so i go out in the morning and look and sure enough the bolts were about touching the bars.,and if i was going to the point of replacing it($200) give or take i'd also do the balancer and the t-chain while it's off.if it's at 125,000 it's getting about due anyway.

[Hubert]

After you check all pulleys/accesories and tensioner keep it simple and only buy and install a high quality top on the line serpentine belt!!! The 6.5 for some reason: diesel vibration, rubber mounted crank pulley, vac pump, HO waterpump, hydro boost brakes - I don't know but its hard on the serpentine belt.

I learned my lesson and have seen a cheap belt stretch out and start to squeal in just 20 or so miles. And seen quality name brand belts last only 500 miles. This is one of those items that it is worth it to buy the best.

I have read many recommend Goodyear and AC Delco belts. Definately stay away from the discount auto part store brands!!!!