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Discussion Starter #1
Installed a brand new AC Delco tensioner with a brand new Gates 'Micro-V' serp belt that I bought at CarQuest for around $30, so not exactly a cheap belt. I did some research on here and found a lot of reports of the cheaper chinese rubber belts over-stretching, so I went for the mexican made Gates, which was recommended in a thread here somewhere.

Upon installation the belt wear indicator marks on the tensioner registered the the RHS of the scale, where it should be. Now after just over 200 miles it's stretched out past the LHS of the wear indicator scale...WTF:confused:

The new tensioner was noticably more difficult to leverage than the old one and the Gates belt looked and felt like quality, so I'm inclined to think that the spring in the new tensioner is just too strong.

The pulley bearings in the old tensioner were on the way out and I could have just replaced the pulley. But the old tensioner appears original so I figured the spring might be getting tired and could possibly break, so I opted to replace the whole unit. Now I'm either gonna have to swap out the new pulley onto my old tensioner and buy another belt, or return complete tensioner for credit and just get a new pulley and belt...I'll probably do that because I hate taking it in the a$$ for crap parts :mad:

But I still want to buy an additional tensioner to carry as an emergency spare. So, any experienced recommendations on a QUALITY tensioner and belt combo?
 

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Discussion Starter #3
By "GM" I assume you mean AC Delco? 7+ years is an awesome service life for a serp belt. I hope today's GM belts have the same quality. It looks like Gates are making alot of AC Delco parts these days. The new tensioner is supposedly AC, it came in an AC box but there is no branding on the part itself and the part# on the box is 38118, which happens to be the same part# for a Gates tensioner which looks identical to the AC tensioner in online sample pics - Hmmm...

I guess I should just go to the dealer and inspect a belt. If it's not a Gates I'll take a chance on it but I won't be surprised if it over-stretches because It really feels like this new tensioner is too tight. Which brings me back to my question; Anyone else have any success with a non-AC/Gates tensioner?
 

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Have you used search??? I have read some of this issue before but I forgot whether it is here or tts forum. IIRC, they are using Dayco tensioner and have same issue.

Have you tried to exchange the belt and see if it is bad belt or old stock belt?
 

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We never, ever use Gates. Those things stretch like rubber bands. Dayco or Genuine stuff is the best.
 

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We never, ever use Gates. Those things stretch like rubber bands. Dayco or Genuine stuff is the best.
i would never use dayco, i had 1 belt that when i put it on had a hard spot and would not flex right causing the tensioner to bounce every time it hit it
 

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I have a Terex TS14 Scraper (6.5L QSB Cummins), Rear motor does the same thing to OE Belts. Gotta run Delco on it. Unexplained.
 

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Discussion Starter #8
Have you used search???
Did you read my OP??? :p::D

I did some research on here and found a lot of reports of the cheaper chinese rubber belts over-stretching, so I went for the mexican made Gates, which was recommended in a thread here somewhere.
 

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Discussion Starter #9 (Edited)
I have a Terex TS14 Scraper (6.5L QSB Cummins), Rear motor does the same thing to OE Belts. Gotta run Delco on it. Unexplained.
Delco or Dayco?

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I picked up a new 'GM' belt from the stealer; $89.47 + tax :eek::mad: - I'm pretty sure it's a Gates even though it's GM labeling

The upper belt is the $30 one from CarQuest, that stretched. CarQuest branded belts are made by Gates, according to counter clerk.

The middle belt is a Vac-Pump-delete 100" spare that I carry in case of vac pump failure. It is also CarQuest (approx $30) and clearly shows 'Gates' logo.

The bottom belt is the new $89 'GM', which has markings and patent #'s suspiciously similar to Gates.




After just over 200 miles, the tensioner was all the way to the over-stretch stop, so it was no longer providing much in the way of tension. Slippage was bound to happen sooner than later - Tensioner with stretched belt:



Tensioner immediately after new GM belt install, but before start-up:



Tensioner after 15 mile test drive:



I will post additional photos if any excessive stretch occurs. Once I've verified which new part(s) are substandard (tensioner/belt) I will be returning for full refund. On the positive side, I will also post back with the good news, should the GM belt hold up.

Got an interesting opinion from the GM parts guy; he thinks that the CarQuest belt is not strong enough for the new AC Delco tensioner because aftermarket belt specs are 'averaged' to conform to multiple cross-brand applications, i.e. the belt might be made to run on the tensioners of GM and any other brand; Ford/Dodge/Toyota, etc, that requires a 101" 6 ribbed serpentine belt, and therefore is not designed to specifically run on a GM tensioner - Interesting theory, no?
 

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Have you used search??? I have read some of this issue before but I forgot whether it is here or tts forum. IIRC, they are using Dayco tensioner and have same issue.

Have you tried to exchange the belt and see if it is bad belt or old stock belt?
Tahoe, did you search TTS???? It must be at TTS. I remember TurbineDoc have the same issue.

I am flip flopping between the 2 forums, sometimes I am not sure where I read things.

If you are not a member there, sign up and a lot of the people here from the beginning is now there.
 

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I have had these problems myself. Seems like the new belts all stretch. I have a collection of almost new stretched belts. My solution is to fine tune the belt adjustment by putting washers under the ac compressor once it has stretched.
 

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I have had these problems myself. Seems like the new belts all stretch. I have a collection of almost new stretched belts. My solution is to fine tune the belt adjustment by putting washers under the ac compressor once it has stretched.
Very creative soloution.
 

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Discussion Starter #15
Thanks for all the input guys!

I've read everything I could find on the over-stretching belt issue, both on here and on TTS. From that I feel like I have a deeper insight into the problem but there doesn't seem to be any real consenus on a universal solution. So it looks like it will have to be a matter of trial and error until I find what works, in my case. May use Glagulator's idea, if it comes to that. x2 on the creativity for that one!

The good news so far is that the belt wear indicator is holding steady after 100mi. The bad news is that I have a new, very disconcerting noise coming from what sounds like the oil pan :eek:. My first suspicion was the crank pulley going bad as that would play right into the belt stretching mystery. I had inspected it very closely about 2000 miles ago when I did the Fluidampr install and it was in perfect shape then. To be certain, I pulled the splash shield and re-inspected the pulley and it still looks fine; No wobble when running, no cracks or separations in the rubber, no sign of cracked spokes and no sign of metal to metal contact between the outer hub spoke stops and the inner hub.

So it looks like I have a new pending problem to start another thread on :(

I'll report back here on wether or not the new GM belt holds up after some significant miles, providing there's no catastrophic failure in the making...
 

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I know its been 5 years but I was wondering how the gm belt held up Tahoe Diesel. I'm having this issue in my 97 savana van 6.5l which only has 80k. As soon as I start it up with a new belt, the tensioner bottoms out. I,ve put the shortest belt possible and still bottomed out the next day. New a/c compressor, tensioner. Four belts it's stretched. Not sure what to do and it's a big problem.
 

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I started having to use a smaller than stock belt on my trucks. Very tight to put on new but once they stretch there about right. Seems belts arnt what they used to be
 

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I'm having the same problem...I used a Continental 4060998...it was a little tight to put on and has since went past the lower wear mark.:shake:
 

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FYI.....put washers under the AC compressor. The washers measured .109"..it brought the belt back to 60% on the wear indicator. Put a couple miles on it so far.....
 
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