Serpentine Belt 2001 Workhorse 8.1 Vortec

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Henry J Fate

Well-known member
Jun 14, 2018
Trying to find the GM part number for the serpentine belt on a 2001 workhorse 8.1 vortec. Any help would be greatly appreciated.
Thank you Master Mark. I had seen some controversy posted concerning the length. I suspect it must be a standard workhorse belt and not modified for the mh application. Hopefully no issues there as I may be replacing it out on the road early April and wont have the original one out to compare until the install. Thanks again.
As a retired shop owner and mechanic my recommendation is dont wait for it to fail. If you think you might have to replace it out on the road that would be the worst place to do it. Do it at home and save the old one for a spare. Same year, make and model could have different parts installed, ie; alternator size, a.i.r. pump, etc. A 2001 belt is likely to be a epdm belt, they dont crack like older belts, they just wear down and either slip on a pulley or break. Most of the time you cant tell just by looking at the belt for wear.
Excellent advice. Probably much better to do it before departure. I have a stop planned about 1500 miles into the trip and would have some help there before heading out for another 1500. I think I will tackle it before heading out. I have not evaluated the process yet but I assume that once I figure out the access point, it will only require the tension pulley to be relieved and it should come off. If anyone has any experience with the process, it could turn out to be very helpful.
I concluded years ago that mine is the P32. I will double down on that finding to be sure
Not sure, but I used a Continental 4061030 on my 2002 P32 with 8.1L according to my Amazon purchase history from 2017
Trying to find the GM part number for the serpentine belt on a 2001 workhorse 8.1 vortec. Any help would be greatly appreciated.
I believe there are two different belts they used on the 8.1 so a tape measure is your friend.

Also.. Mine split lengthwise than 1/2 broke and made a mel of a hess.. I spent a good hour or two on my back cutting the mess out of the area (Thankfully no secondary damage) and after doing my best decided I did not have what was needed to replace it.. Found a shop that could do it.. Took 'em less than 30 minutes.. I did not even have time for a cup of coffee and they were done.

They knew how and had the facility (Truck size grease pit) to work on it easily.
Hopefully I have enough room to get up in there. If not, I guess I will need to pay the shop time. I will get a good look at it when I change the oil in the coming weeks.
I replaced my tensioner pulley at the same time. I recall clearance wasn't plentiful, you're basically working inside the radiator fan shroud. A second person might be handy to hold the belt in place on the crank pulley while you argue with the tensioner from up top.

I snipped this from somewhere and had it on my phone, because no matter how much you think the routing is obvious this will save an iteration or two.

Mark B.
Albuquerque, NM

Henry: taking a belt off is always easier than putting a new belt back on. First of all when you remove used belt and hold it up it is round. Take a new belt out of the pkg and hold it up, now picture trying to put that belt on by yourself. Mark is right, it often takes 2 people to put a new belt on. Picture holding the tensioner, holding belt on bottom pulley and putting belt on tensioner pulley. Have a friend close by if you do this by yourself. Now is the time to check all pulleys, any noise or looseness ALWAYS REPLACE.
Thanks for all of the guidance. I have not taken a good look yet but I know it will not be an easy task. Last oil change I took a quick look. Although it wont be easy, its time to take care of it. Are there any part numbers available for the tension pulley ? Thanks for all the great help.
I use a 3/8" ratchet with a hinged head and long handle to release the tensioner. I have a 12" or so pipe extending the ratchet handle. This, along with the hinged head allows me to hook it behind something to hold in the tension-removed position. It's then easy to position the belt and release the ratchet.
I do this all from under the coach. It takes longer to get the tools out than do the job.
Even with the diagram it's easy to get confused when looking at it from underneath.
I have a spare tensioner for my coach, I can get the number off of it tomorrow if no one posts back before then. Never mind I found it in my amazon order history from 2017 it is an AC Delco 12557682 The price has dropped an insane amount since then, it was $59 now showing $17
Tensioner: WH 12581203
Gates 38258
Gates 38006 (Pulley Only)

When I did mine I only replaced the pulley. Also replaced the idler:

Idler: WH 12580771 Replaced by GM 12669569
Gates 36299
Hayden 5975

Mark B.
Albuquerque, NM
Thank you. Every post has been very helpful. I did not know there was an idler pulley. Best to replace that too. Gona start getting things ready to roll beginning next week. My list is long. Will be a few weeks before getting to the belt. Hopefully I will have all the correct parts by then. Thank you to all.

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