8.3 Cummins, Water Pump/Alternator Squealing Belt

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8.3 Cummins, Water Pump/Alternator Squealing Belt

July 12, 2012, 03:16:41 pm

If you have a 1996, '97 or '98, 8.3 Cummins Mechanical and have a squealing water pump/alternator belt (even if only when the alternator is working hard), I may have a tip for you. I wasn't able to find this issue in a ForeForums search.
I have always had difficulty keeping the right water pump/alternator belt installed on my U270, 8.3-325 Cummins. Some FT service centers have told me that I have the wrong belt (wrong part number) installed and have talked me into changing to a different belt, but it has always ended up with either a "too tight" tensioner or a squeaking/squealing belt because the tensioner is too near its "fully relaxed end".
Here are several Gates part numbers and the problems I've experienced:
1. K080605 60.59" effective length 3" too short to install My Owner's Manual (which agrees with Barry's listing) is clearly not correct with this number for our coach, for unknown reason(s). I'm not sure how you reflect that efficiently in your information, Barry. It may well be a good number for others.
2. K080635 63.74" effective length This is the belt listed on the NAC "Belts/Filters list" that NAC Parts hands out. It can only be installed by removing the alternator brace/installing belt and then reinstalling brace (in order to just barely sneak the belt over the lipless idler pulley). Clearly not convenient, but I have successfully used this method for many years (before the next listed belt became available). It also tends to run the tensioner very near maximum tension, although I've never had any problems with our alternator bearings.
3. K080638HD 63.80" effective length This may be a newer model number belt (maybe only available in the past few years?) It fits my engine configuration perfectly and the tensioner rides about 1/3 of its way through its travel, when the belt is first installed (about 1/2 way after 25K to 30 K miles in service). The "GREEN STRIPE" Gates Model (HD designator) is much longer lasting (I get close to double the longevity).
4. K080645 64.67" effective length Tension idler too relaxed/belt squeals all the time I've had this happen before in NAC and TN and should know better. But, without mentioning it, NAC substituted in this belt the last time I was there (last fall) and I missed seeing it before I left. It was quiet for about 50 miles and then it started to squeal. Drives me crazy, because the tensioner can't be repositioned (detent hole would have to move in the wrong direction, making the tensioner run into the drive pulley).

So, many of you are probably already aware of this and on top of the situation, but I thought I would mention it as I just put a new K080638HD on today and it sure is much nicer.

Peace and quiet again!
FWIW,
Neal

Re: 8.3 Cummins, Water Pump/Alternator Squealing Belt

Reply #1 – July 12, 2012, 03:55:55 pm

Neal,

I replaced both tensioners & belts this Spring and used the K080645 for the water pump alternator...no squeling. The K080465 for the hydraulic pump does squeal, but a little squirt of belt dressing quiets things right up. I'm assuming it's okay to use that stuff on these belts.

Peter

Re: 8.3 Cummins, Water Pump/Alternator Squealing Belt

Reply #2 – July 12, 2012, 04:32:43 pm

Thanks for the update. I have been carrying a K080605 for some time as a spare. Because of your post, I just checked it as compared to the installed belt. It is obviously much shorter. I could find no markings on the installed belt. I will get a K080638HD to carry as a spare.

The NAPA 25-080465 seems to work fine on the hydraulic pump. The previous belt squealed. I replaced the tensioner with a Cummins unit from FOT and the belt still squealed. FOT installed the 25-080465 and it has been quiet.

Re: 8.3 Cummins, Water Pump/Alternator Squealing Belt

Reply #3 – July 12, 2012, 05:19:12 pm

Good info. I've always thought the alternator belt was a bit tight, will give this one a try. Thanks, Chuck

Re: 8.3 Cummins, Water Pump/Alternator Squealing Belt

Reply #4 – July 12, 2012, 09:15:05 pm

Would like to add info concerning brand name's of belts, V & Multigroove types.
If you get a Cummins Belt it will be a Dayco, I would take that Cummins number and go to a NAPA shop and cross it to a Gates number.
We have much (too much) experience with weak Dayco belts, V belts will turn over at higher RPM and/or break. The Multigroove belt will simply have a short life and break.
We will never use a Dayco except in temporary until we get a Gates belt on.
Surely someone has had great luck with a Dayco, well they are just lucky.
FWIW
Dave M

Re: 8.3 Cummins, Water Pump/Alternator Squealing Belt

Reply #5 – July 13, 2012, 12:57:18 am

Quote from: Dave M – July 12, 2012, 09:15:05 pm

..................................Would like to add info concerning brand name's of belts, V & Multigroove types........................................

Good points Dave.
From my experience, NAPA sells Gates and they sell their own NAPA Belts. The numbers are the same (with different prefixes) and the dimensions are the same, but also from my experience, the Quality doesn't seem to be the same:
eg. NAPA 25-080645 = Dayco 25-080645 = Gates K080645 dimensions wise. All are shown as 64.67" effective length (notice the length is also embedded, at least roughly, in the part number), but the Gates seem to outlast the other two by roughly a factor of two. If one pays a little more for the K080645HD, which is the "Green Stripe", extended service belt, the useful lifetime goes up by another significant jump (Dave Head clued me into that several years ago).
A local big rig truck parts store tells me that there are really only two large producers of our type belts and tensioners (Dayco and Gates). He says the NAPA belts are built by Dayco and are just stamped with the NAPA LOGO and part numbers.
The water pump/alternator belt that FOT put on last fall was not a GATES, as I implied in my first post. It was a NAPA 25-080645. The belt they took off was a Gates K080635 that had nearly 30K miles on it and was just beginning to squeal a bit, and then only under heavy alternator loading.
I had recently developed some significant tensioner "bobbing" and I was replacing my tensioners (for the first time) at 180K miles. FOT recommended fresh belts to complement the new Cummins (Dayco again) tensioners.
But shame on me, I knew I wanted the exact belts that I had installed, told FOT so, but then I didn't go look up the specific GATES K080638 and K08465 part numbers for them, as well as forgot to check to see what they had installed before I left. The new NAPA alternator belt started to squeal 50 miles down the road and was horrendous by the time we got home to NH. The FOT installed NAPA 25-080465 on the hydraulic pump is still quiet and doing fine at 5000 miles. Of course, having had the belts and tensioners off numerous times before, I should have done my own tensioners and belts, all with the higher quality GATES, but we were in a rush, I had several other irons in the fire and I just didn't follow my own intuition.
I did gripe at FOT about the belts as well as a "no-charge" grease stain in the carpet, in the follow-up Quality survey, but I never got any response. And I didn't follow-up on that either. I'm seeing a pattern here!

Still kicking myself on both counts. More my fault than theirs, but different from the "Old Days".
FWIW,
Neal

Re: 8.3 Cummins, Water Pump/Alternator Squealing Belt

Reply #6 – July 13, 2012, 10:05:54 am

Belt tensioners ARE a wearing item.

Here is an excellent short video by Gates Corp: Failed versus a good belt tensioner.

Brett

Re: 8.3 Cummins, Water Pump/Alternator Squealing Belt

Reply #7 – July 13, 2012, 10:41:27 am

Quote

Belt tensioners ARE a wearing item.

Here is an excellent short video by Gates Corp: Failed versus a good belt tensioner.

Brett

Brett, That little video is the best example of KISS that I have seen, A CD should be in every new owners set of manuals .
Gary B

Re: 8.3 Cummins, Water Pump/Alternator Squealing Belt

Reply #8 – July 13, 2012, 10:52:48 am

Yes, I use that in all the diesel maintenance presentations I do. Even inserted it in the original Caterpillar Corp maintenance presentation I do at the FMCA Conventions.

Brett

Re: 8.3 Cummins, Water Pump/Alternator Squealing Belt

Reply #9 – July 13, 2012, 11:17:58 am

Quote from: Neal Pillsbury – July 12, 2012, 03:16:41 pm

If you have a 1996, '97 or '98, 8.3 Cummins Mechanical and have a squealing water pump/alternator belt (even if only when the alternator is working hard), I may have a tip for you. I wasn't able to find this issue in a ForeForums search.
I have always had difficulty keeping the right water pump/alternator belt installed on my U270, 8.3-325 Cummins. Some FT service centers have told me that I have the wrong belt (wrong part number) installed and have talked me into changing to a different belt, but it has always ended up with either a "too tight" tensioner or a squeaking/squealing belt because the tensioner is too near its "fully relaxed end".
Here are several Gates part numbers and the problems I've experienced:
1. K080605 60.59" effective length 3" too short to install My Owner's Manual (which agrees with Barry's listing) is clearly not correct with this number for our coach, for unknown reason(s). I'm not sure how you reflect that efficiently in your information, Barry. It may well be a good number for others.
FWIW,
Neal

How about like this

cummins-c8.3-belts-hoses-filters
Thanks for the update on your experience.

Re: 8.3 Cummins, Water Pump/Alternator Squealing Belt

Reply #10 – July 13, 2012, 12:06:02 pm

Barry,

I like the link. Consider a couple of more changes. 1) Look at the heading. From my chair it looks like "UMMINS" rather than "CUMMINS." 2) For those of us who might not immediately notice and follow the link, put a note or notice by the link that says something like "Check here for more information."

Thanks for continuing to update the great resource that you provide.

Re: 8.3 Cummins, Water Pump/Alternator Squealing Belt

Reply #11 – July 13, 2012, 12:44:26 pm

Quote from: J. D. Stevens – July 13, 2012, 12:06:02 pm

Barry,
I like the link. Consider a couple of more changes. 1) Look at the heading. From my chair it looks like "UMMINS" rather than "CUMMINS."

From my chair it looks that way to. A testament of my typing skills

It is corrected. Thanks for catching it.

Quote from: J. D. Stevens – July 13, 2012, 12:06:02 pm

2) For those of us who might not immediately notice and follow the link, put a note or notice by the link that says something like "Check here for more information."

Thanks for continuing to update the great resource that you provide.

Usually the highlighted link tells you there is more info. But if you hover over it, it states that there is more info. Trying to keep it consistent.

Re: 8.3 Cummins, Water Pump/Alternator Squealing Belt

Reply #12 – July 13, 2012, 02:06:14 pm

Quote from: Barry Beam – July 13, 2012, 12:44:26 pm

Usually the highlighted link tells you there is more info. But if you hover over it, it states that there is more info. Trying to keep it consistent.

Nice! I should follow the advice I give to Marilyn, "Hover over the link and see if it provides hints."

Re: 8.3 Cummins, Water Pump/Alternator Squealing Belt

Reply #13 – July 13, 2012, 06:48:39 pm

Quote from: Barry Beam – July 13, 2012, 11:17:58 am

How about like this
cummins-c8.3-belts-hoses-filters
Thanks for the update on your experience.

Barry,
Works great for me.
Thanks again for all that you do so well for us.
Neal

Re: 8.3 Cummins, Water Pump/Alternator Squealing Belt

Reply #14 – April 16, 2015, 11:46:32 pm

I'm bumping this because today I tried to install the belt called for in my FT manual (K080605, 61 1/8 inches) and like Neal wrote, it does not fit! And I bought two of the HD belts from amazon--back in Sept and can't return (anybody want them?)

Previous owner had a 80645 on it, but it's too loose, and it and the used spare are both missing part of the belt (1 groove).

Looks like K080638HD is the ticket!

PS: replaced both tensioners. 80465 fits perfectly for the hydraulic pump.

Re: 8.3 Cummins, Water Pump/Alternator Squealing Belt

Reply #15 – April 17, 2015, 12:33:34 pm

Really pays to check when you buy a coach for spares and the belt fit. This is an eight rib belt and NAPA/Autozone/etc won't have any eight ribs in stock. Good to buy ahead of time online as some retailers will charge up to $125 for this Gates Green Stripe fleet belt.

Ours broke an eight rib belt the next day on the way home after we bought it in N. Carolina. I spent a lot of time trying to find a six rib at a local parts store that would fit.

Foretravel misses on belt length and number of grooves on some engines. With a belt tensioner, a few millimeters make a big difference.

Pierce

Re: 8.3 Cummins, Water Pump/Alternator Squealing Belt

Reply #16 – April 18, 2015, 08:45:09 pm

Krush,

My 2000 U295 with 350 Cummins 8.3 definitely requires a K080680 for the alternator and water pump; it uses a K080465 for the hydraulic pump. I looked at the drawer of spare belts I inherited and found two new K080465's and a brand new Napa 080680.

However, my new Napa belt has a HOLE in it! It almost looks like it was bring your daughter to work day and he turned her lose with a clothing type price gun. It really looks like something was punched through the belt from the rib side and poked out the smooth side. I cannot imagine another way that such a hole got there.

Obviously, I don't have any receipts, but I think I will take it to the Napa store in Tulsa and see if they are willing to replace it. I have attached a picture. Sorry it is a little out of focus (probably too close - guess I should use my real camera). It does show the size of the hole relative to the belt. Meanwhile, it will work good as a spare, as long as I never have to use it.

Anyone seen this type of damage to a new belt before?

Thanks,

Trent

Re: 8.3 Cummins, Water Pump/Alternator Squealing Belt

Reply #17 – April 18, 2015, 09:34:40 pm

I just checked the belts on my 8.3 engine. Gates KO80605 Green stripe and Gates KO80645 Green Stripe. I have never had any trouble or squealing from the belts. I'm also carrying a couple of new spares with the same numbers and a used Napa 080605. I'm sticking with what has worked for me. I did replace the tensioners a few years ago. There is a solid bar on the bottom of the alternator to the block where there could be an adjustable rod for belt tension. Perhaps this bar is a different length on other 8.3 engines and that could be the reason for a different length belt. On my engine the bar could not be any shorter, but it could be longer requiring a longer belt.

Re: 8.3 Cummins, Water Pump/Alternator Squealing Belt

Reply #18 – April 19, 2015, 09:53:48 am

Quote from: TulsaTrent – April 18, 2015, 08:45:09 pm

( ...guess I should use my real camera).

Yes, I concur.

Re: 8.3 Cummins, Water Pump/Alternator Squealing Belt

Reply #19 – April 20, 2015, 09:12:04 pm

K080638HD came in today and I went to put it on....can't get it on without loosening the alternator and swinging it over. I'm going down the road, so that's what I did. I still have the old belts for spares. Prying the alternator back and getting the bolt in the support is a two-man job and I can't do it alone on the side of the road. My 80645 belt that is on it was missing one or two grooves, so it was about 80% as wide as a new one....thus probably stretched out. Previous owner (sigh).

I replaced the tensioner--new one doesn't bounce. I'm going to order a 80645HD to throw in for a spare. The 80638 is fine for now, but just too hard to get on. Also, there is movement in the tensioner, but it is pretty far up in its travel.

From the gates catalog:

K080630HD............ 63 5/8
K080638HD............ 64 3/8
K080645HD............ 65 1/4
K080649HD............ 65 1/2

Re: 8.3 Cummins, Water Pump/Alternator Squealing Belt

Reply #20 – April 21, 2015, 10:22:32 am

That alternator should not have to be moved to put the belt on, sounds like a short belt OR idler is not retracting enough to allow belt to be put on. My method was to put belt on alternator and drive pulley and then slip it over idler last while retracting idelr with breakover bar.
Gary B

Re: 8.3 Cummins, Water Pump/Alternator Squealing Belt

Reply #21 – May 14, 2015, 02:31:17 am

Update!

I took the Napa belt with a hole in it to the local Napa dealer. They replaced it with a brand new one for free!

Thank you, NAPA,

Trent

Re: 8.3 Cummins, Water Pump/Alternator Squealing Belt

Reply #22 – May 14, 2015, 09:22:20 pm

SO MANY NUMBERS

thinking maybe mine should be like Trent cites for his 2000 (also 295 model).

Better use my AITA discount at NAPA for a couple spares. don't think the PO left me any

Re: 8.3 Cummins, Water Pump/Alternator Squealing Belt

Reply #23 – May 15, 2015, 12:06:21 am

Quote from: TulsaTrent – April 18, 2015, 08:45:09 pm

Sorry it is a little out of focus (probably too close

Discovered that my smart phone (Samsung Note 4) will focus on any spot I touch on the screen; neat!

Trent

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