Duramax Fan Belt

[Roy W]

I recently ordered a new serpentine belt from JK for my '05 with 92,000 miles. The OEM belt shows no signs of cracking or wear and the indicator on the tensioner is in the middle of the two marks. With 92K on the original belt would you carry the new one as a spare, or replace the OEM belt with the new one and carry the OEM belt as a spare ??

[conway]

Replace. Don't gamble that it will last. It would probably fall apart at the most inopportune time.

[DmaxMaverick]

Flip a coin. There's no guarantee that either belt is more/less serviceable than the other. I replaced my original belt at 100K, just because. 50K later, the second belt looks worse than the first. Same with the tensioner (with the original now back in, and no problem). Both are OEM, same part numbers.

[Mark Rinker]

Those serpentine belts are incredibly durable. Don't recall ever hearing of one break, reported here on TDP.

I have never had one fail, in >600K Duramax miles. Can't recall if the '01 or '02 got a new one - if they did it was because they started looking bad..."cracks per inch" thing...

I'd throw your new spare under the seat, and see how many miles you get out of the first one. Whats the worst that could happen?

[DmaxMaverick]

Actually, there's a lot that can happen, in the "worse" category. When a belt shreds, it can be like a weed-eater under the hood. I haven't seen one happen on a late model truck, but it did on my wife's care. It destroyed the hood insulation, numerous wire harnesses in the area, the crank position sensor (behind the balancer), and probably the water pump I had to replace some time later. Hers was overdue for replacement (according to miles/time), but showed no sign of letting go before it did.

[richp]

Hi,

I thought I was being smart when I replaced my belt at 100K on my '01 truck. Within a month afterward, the tensioner froze up. The belt sizzled for about 10 seconds with a nice high pitched sound and smell of burning rubber -- and then burned through.

Of course this took place out in the middle of the country while towing a fifth wheel trailer. I managed to horse it (no power steering any more) into a farmer's field and with his permission "camped" there until I could get towed into a town and waited for a part to come in from the big city.

I still think it was smart to preemptively replace the belt, as I did when my U-joints got 150K on them and the stock alternator had about 125 K on it. With all the cross-country travel I do while towing, I try to think about what easily replaceable items might give me a headache in the middle of nowhere.

FWIW.

[Mark Rinker]

My 2002 got the only alternator I've replaced so far - at about 250K miles!!!

Come to think of it, it did get a belt and tensioner, but not sure at how many miles...probably at ~170K when injectors, thermostats, glows and waterpump were done...or right around that time.

When the hood finally comes open, and the checkbook is out - I like to throw LOTS and LOTS of new shiny wearable/replaceable parts in there, while the mechanic is at it. ;)

[DADGLW]

mine went about 1000 mile ago.what a mess . it wrapped around the alt so bad i had to take off the pulley.pieces everywhere. replaced all iders while i was there..........

[Kennedy]

One other note on idlers etc.

One of my helpers has a 2001 with around 100k. Original pulleys had like 90k and while they seemed OK were a bit free spinning so he decided to replace the tensioner etc. Less than 9,000 miles (maybe it was 900?) later heading home from here in the rain, the replacement (NAPA?) locked up. Thankfully he had the original with him and swapped it back on. I'll stick with the OE for tensioners and pulleys.


I've offered a nice HD belt (import) for many years now, I just finally got motivated to list them on the site. They have been extremely durable and economically priced to boot.

[DieselDavy]

I'm with DMax, Put that new one on!
When mine let go, to took out the hood insulation, ripped numerous wires loose and tore a temperature sending unit loose from the radiator! (had to remove antifreeze and re-solder sending unit mount.) That will teach me!

[DADGLW]

replaced my idlers with oem.only way to go...........

[Dinkie Diesel]

replaced my idlers with oem.only way to go...........

I have a problem brewing but not sure what to think. I had a clacking noise from the belt. I thought it was the belt itself. I replaced the belt many months/years ago on my 2001. Now with 90,000 miles on it the clacking noise has come back. I popped the hood and see the tensioner going ape, fluttering and the belt between the crank pulley and the first idler (remember mine is a 2001, single alternator) is flopping. I bought a new tensioner idler pulley (bearing included) but not the entire tensioner. I bought a Gates brand from O'Reilly - $20, China bearing. I removed the old one and it had a tiny bit of play. Put the new one on and closed the hood. I thought all was well. Today I hear the noise again. Tensioner is still going ape still. There are two more idlers near the tensioner. I'll check them tomorrow. Is there anything inside the tensioner besides a spring that would cause the flutter? I figured a new idler on the tensioner would solve the problem baring a weak spring, yes? Does everyone agree that original GM parts are better?

Thanks


Jeff

[DmaxMaverick]

I have a problem brewing but not sure what to think. I had a clacking noise from the belt. I thought it was the belt itself. I replaced the belt many months/years ago on my 2001. Now with 90,000 miles on it the clacking noise has come back. I popped the hood and see the tensioner going ape, fluttering and the belt between the crank pulley and the first idler (remember mine is a 2001, single alternator) is flopping. I bought a new tensioner idler pulley (bearing included) but not the entire tensioner. I bought a Gates brand from O'Reilly - $20, China bearing. I removed the old one and it had a tiny bit of play. Put the new one on and closed the hood. I thought all was well. Today I hear the noise again. Tensioner is still going ape still. There are two more idlers near the tensioner. I'll check them tomorrow. Is there anything inside the tensioner besides a spring that would cause the flutter? I figured a new idler on the tensioner would solve the problem baring a weak spring, yes? Does everyone agree that original GM parts are better?

Thanks


Jeff

It's probably gonna be another idler, or an accessory going south. Use a screwdriver with a ball-end handle and hold it on the belt over the pulley until it just touches (very light touch, support your hand holding it so it's stable, use the ball end, NOT the bit end). You should be able to feel the roundness of the pulley. Do the same for the middle of the belt and edge of the pulley. Engage it gradually and note the rhythm. A repeated rhythm with all the pulleys is a belt defect. A bad pulley will stand out. With the belt removed, the pulleys/idlers should turn freely and near silent, but with some resistance and slow down quickly. A bearing that spins freely and just keeps on spinning, or makes noise like a roller skate, is bad. Alternator and PS pump should not have any play. The A/C pulley should act like an idler, and not turn too freely or make noise.

OEM is better for pulleys/tensioners. Gates has been good for belts.

[leolkfrm]

just changed both my idlers..one was rough t turn , the other was out of grease and wobbling...could not find a none china idler pully for the tensioner but was able to get a good domestic bearing and press it in..$10.00

[dually2002]

Belts wear and get thinner. Changed my belt at 90k and orignal belt was intact but noticeably thinner than the new belt. Stopped the squeeling. Serp belts wear on both sides.

[EdHale]

I had both idlers and the tensioner replaced on my truck at 107,000 as well as the belt. It just now occurred to me after reading this thread that the chirp that my truck has had when shutting it down has stopped. It has done this since day one at 12 miles on the clock. Hmmmm?

All new parts are OEM done at a dealer.

[greatwhite]

swap it out, chuck the old one in under the seat as a spare.

I change out the idelr around 100,000 kms or so.

I also chuck the old one under the seat just in case.

But then again, I'm driving a 98 6.5 and keep a spare PMD and throw in a spare injection pump for longer trips.

"Spares" is the watchword in my rig......:(