belt tensioner

[EscaladeDiesel]

My belt seems loose and squeals upon start up then once warmer stops, but the belt still seems loose and has some slack when runnign. Can the tensioner be tightened or must it be replaced?

[autocrosser]

Tensioners wear out. A lot of times the lock up and can't move. this may be the case that it can't move to tighten the belt anymore. I've had to replace the onk on my Chrysley wagon twice in 100k. The truck tensioner is still going strong at 100k.

I also just replaced the belt on my daughters Dodge van and our chrysler van due to a little squeak that was caused by the belt. Spraying a little liquid on the belt would shut it up and both of them would go back to squeeking in a little while. Tensioners were ok.

[ucdavis]

I'll ditto what Autocrosser said & add:
Tensioners fail in different ways. I had one that would cause the belt to skip a rib, putting one rib off the ribbed pulley wheel; that wore the rib out, split it off & made a belt that was one rib shy.
Then it kicked the belt out a second rib... Some how it had a bias, pushing the belt sideways. No squeal, no tension problem, etc.
Replacement is the easy way out.

[Hubert]

How many miles?

Keep in mind the 6.5 is kind of hard on the serpentine belt. My quess but I think the vac pump and maybe the high volume waterpump put added strain on it. My 97 K2500 seems to stretch a belt out rather quickly. The tensioner starts off "high" then creeps to its maximum travel down. My first belt replacement I bought a cheap one and it lasted maybe 20 miles before stretching out completely and squealing. Then I bought an inexpensive belt (not a cheap one) it lasted maybe 500 miles then stretched out completely and started squealing depending on rpm and acceleration. I then bought an expensive belt its thicker and has a stickier back side it stretched out too ~ but doesn't squeal. My tensioner is dang near at full travel and been doing fine for 10,000-15,000 miles I think. The tensioner can go bad and several have but you should be able to tell if it is. Look at the tensioner and actuate it through complete travel a few times - see how it feels and moves. Make sure its not trying to come apart, twist, cock over, and the pulley feels smooth and free. If it looks straight feels smooth, has a good resistance to it, and the belt runs true and smooth I'd just replace the belt with a HIGH QUALITY ONE. I think the belt on a 6.5 is more likely good for about 60,000 +/- miles not the 100,000 miles on other gas engines.

[EscaladeDiesel]

Who makes the best belt, and where do you get it?

[KallyI]

How long ago was the squeaking belt replaced, and was it doing that with the previous belt? I replaced my belt in August this year, and right after I did it, the belt did the same as what you are describing. I took a better look at how I had the belt routed, and discovered that I had it wrong. I corrected the routing, and the squeal stopped, and the tensioner ended up about in the middle of its available travel.
That tensioner was replaced at 60078 kms, (warranty was to 60000). It blew apart on me at about midnight, -30 degrees, and on a remote road. Of course I lost all the power accessories. Thank goodness it was as cold as it was, or I would have overheated as well. The stealer agreed to provide the part, if I would pay for the labor. The truck now has 220,000 kms, with no further tensioner trouble.

[autocrosser]

Who knows what the beat belt is?? I just try to buy a major manufacturer. I believe the one I got was a goodyear.

As far as the tensioner you should be able to move it smoothly plus and minus from the position where it is residing with the belt on. I think there's bearings inside that wear out and lock up the tensioner so that it can't move properly to keep the belt tight during fluctuations ans flapping. There's marks on the tensioner and bracket that are a relative indication of the belt stretch.

[Hubert]

I dunno the best belt. I am not a name brand shopper most of the time. I ended up with the premium belt at Carquest (can't remember mfg) and its been pretty good. The inexpensive ones at Autozone Poly-clog or something did not do so well. Most people will say the AC Delco is recommended - its expensive though.

Ask to look at them and compare. Feel the texture of the back side, the thickness, ask if it is OEM rated, and compare price.

[EscaladeDiesel]

The belt is from the dealer think it was replaced 2 years ago doesn have many miles as my Suburban only has 50,000 on it. There are no cracks and its in good shape, it only started to make noise after my mechanic replaced the h-balancer and pulley.

[ 12-08-2004, 06:02 AM: Message edited by: EscaladeDiesel ]

[Billman]

I like the Gates belts. I think Dayco is junk.

Napa belts are made by Gates.

[Hubert]

Well if something was just changed that sounds like its not routed correctly. Check the diagram under the hood on top of the radiator shroud or somewhere up front near the latch.

[EscaladeDiesel]

Yes, I checked that too, but it appears to be routed correctly, as best I can tell.

[rjwest]

I have had many belts!!!!!!

Tryed to replace pully on Tensioner, Could not get
the pully with the " Lip " as per original.
Therefore could not get belt to Fit/ or not shread
edges. Napa and Other belts where to long or to short. tryed another pully same problem.


Installed GM Asm( Tensioner & Pully,can't buy seperate) ) installed new
NAPA belt , Was ok, tensioner was aligned
with the first 3 marks, But not for long,
Bely streched to where tensioner pully was at full travel, ( down at bottom of arc ). Installed
GM belt ( Goodyear ) NO PROBLEMS , Fixed for many miles......

Installed Turbo Master: Back to same belt problem:.
100" Dayco ( cheap one ) would only last
1500 mile ( 2 ) , tryed Dayco EXPENSIVE 100" belt , Was longer than Dayco cheap belt, Tensioner at full travel.....

Tryed NAPA 99 5/8" belt, can't get over Lip on tensioner pully, Remove Pully, Pull back tensioner, get belt on and install pully.
( Quite a trick , by yourself ).

Tensioner At first marks after 200 miles,
and Belt looks good, Maybe it will work.

If not will try to get a GOODYEAR belt, I think they may be the best.....( Buick has 80K miles on a
gatorback with no signs of wear ).

Bottom line: Next time GM parts for tensioner and
Belt(Goodyear)

[EscaladeDiesel]

WOW, that was a nice and detailed post reply for all of us. THANKS

[gvt]

My tensioner disintegrated last night on the way home from work. At 134,000 miles it seemed to be working fine, no noises and the spring was working fine when I checked it a couple weeks ago. Since the truck overheats really quickly without a water pump I had to get a tow. It ended up costing me $316 with the tow.

More Power did an article a while back recommending replacement of the tensioner as a maintenance item. I believe he recommended replacement if it has over 100K on it. I would second that recommendation! If I had replaced it sooner it would have saved me an $80 tow and a $70 belt that was only a year old.

Kinda made me mad considering this happened 5 days after getting a new injection pump. Live and learn!

[sturgeon-phish]

Are the lines on the tensioner for indicating "proper" tension? If they are, what should a properly operating tensioner sit at?
Thanks
Jim

[damork]

I was never impressed with Gates or Dayco before owning my 6.5, and more disappointed afterwards.

I worked with a former Gates engineer and when we discussed this he confirmed the best belt you can get for a GM or Ford is the OEM.

I've never been able to get over 15,000 miles on either Gates or Daycos on my truck, but the last OEM belt is approaching 40,000 miles. Both the Gates and Dayco's failed while I was driving with pieces flying all over the engine compartment - with no other component to blame.

I've heard good reports on Goodyear's premium line of belts for these trucks but never tried one.