Are you sure the routing is correct? Can't really help with yours because I've never seen one. I can say based on ones I have done that it matters which sheeve or roller you try to slip the belt over last before releasing the tensioner. Try slipping the belt over the alternator last, if no good, try the water pump last, if no good, try the crank sheeve last, ect.

Good point about the routing. And make sure you double-check the reference shown on the engine diagram to what you've done.

On the GM engines I've done, the belt slides up over the water pump pulley last, since the back side of the belt is what rides on there.

You may also want to make sure the belt is centered on the crank damper pulley, as well as the others. With the crank pulley being way down and hard to see, it could be possible the belt isn't seated properly.

GG

Hi Gary, thanks. Yes, the routing is correct. I have installed the belt for this car on numerous times, so I have the routine down pat. :) Plus there is a diagram right there in the engine compartment.

It looks like I need a good 2-3" of additionmal length to get it to fit, and there is no give. But I tried doing the water pump last this time, since the back of the belt runs along the pulley and there is no pulley ridge to get the belt over, but it was a no go. I could even get the belt over the idler pulley before attempting to do the water pump when I tried that! And if I can't do the water pump or idler pulley last, there is no way I would be able to do the crankshaft, alternator, or PS pump last, since they have big pulleys with the V-part of the belt running on them.

Guess I will have to oder a new tensioner from GM and do it all over agian (I doubt they would have it in stock). And drive beltless, just limiting myself to short trips, in the meantime! Either that or see if somehow the parts store can check to see if they have a longer belt.

Julie

On the GM engines I've done, the belt slides up over the water pump pulley last, since the back side of the belt is what rides on there.

You may also want to make sure the belt is centered on the crank damper pulley, as well as the others. With the crank pulley being way down and hard to see, it could be possible the belt isn't seated properly. >

Thanks GG! Yes, I made sure the belt was aligned and centered. And I tried your suggestion about doing the water pump last, as I mentioned above, but then I couldn't even get the belt over the idler pulley before doing the water pump! :)

Julie

Ok, this is what I have learned so far. The idler pulley on my car is fed by the PS pump pulley at 8 o'clock and the crankshaft pulley at 6 o'clock (assuming the idler pulley is in the center of the clock), so the longest distance from the middle of these two feeder pulleys to the farthest point on the idler pulley would be from 7 o'clock pointing at 1 o'clock. So rotating an idler pulley, for example, clockwise towards from 1 o'clock to 2 o'clock would make the distance shorter, hence, easier, for the belt to be installed.

So I compared the old and new belt tensioners. On the old, GM tensioner, the line from the center bolt of the movable tension part to the bolt for the idler pulley is pointing towards 4 o'clock. So when you move the pulley clockwise towards 5 o'clock to put the belt on, the distance becomes super shorter (the shortest distance would be if it were pointing at 7 o'clock when turned clockwise).

But on the new, aftermarket tensioner, the line from the center bolt of the movable tension part to the bolt for the idler pulley is pointing towards 12 o'clock! This means when I turn the idler pulley clockwise to 1 o'clock, the distance actually becomes *longer*, and even harder to put the belt on!! This is unreal!!

There is no way to adjust the movable tension part on this new tensioner, unless I were to pry the over off?? But I unbolted the movable tensioner part from the old GM tensioner, and it appears you can only install it one way, assuming the designs are the same. So there would be no way to adjust this on the new tensioner anyway, so this has to be a design flaw for the aftermarket part. Unless I am reading the mechanism on the old tensioner incorrectly? I can't figure out why the old tensioner does not work, or how exactly it is supposed to work in the first place. I think there needs to be a spring to return the pulley when it reaches the farthest clockwise point, but the spring there is not long enough. The official Chevy shop manual has nothing about rebuilding a belt tensioner.

So it's either live with the design flaw and find a new belt, or get a GM tensioner and try to return the other tensioner to the store, even though it is all dirty now from the installation!

Julie

Did you double check the part #? Those things sometimes change design from year to year. They might have guv you a part for '90 or '92. After market or OEM; if they don't look exactly alike the new one is most likely the rong part.

Take both tensioners back to Advance and show em the difference. Extremely rarely the parts book is rong.

Thanks, yes it was the correct part number, for both the tensioner and the belt. And Auto Zone had the same number.

The belt number ends in 705, which corresponds to the length of 70.5". So maybe if I ask them if they have something like a 745, this would give me 4 extra inches to get the belt on.

**"So I compared the old and new belt tensioners. On the old, GM tensioner, the line from the center bolt of the movable tension part to the bolt for the idler pulley is pointing towards 4 o'clock. So when you move the pulley clockwise towards 5 o'clock to put the belt on, the distance becomes super shorter (the shortest distance would be if it were pointing at 7 o'clock when turned clockwise).

But on the new, aftermarket tensioner, the line from the center bolt of the movable tension part to the bolt for the idler pulley is pointing towards 12 o'clock! This means when I turn the idler pulley clockwise to 1 o'clock, the distance actually becomes *longer*, and even harder to put the belt on!! This is unreal!!"**

Sounds like they gave you the wrong one. Take it back and beat them over the head with it. Then try NAPA. Costs more than AutoZone but is often times worth the difference. jmo

Thanks Gary. I called Carquest, and they have belts 5" longer, which would work on this tensioner. It is supposed to be the one for my car, btw. But I think it is a design flaw, not that they gave me the wrong part number. The dealer also has new tensioners in stock, but they cost $120-$139, vs. $54 for the one I bought. So I will first try sticking with the new, (incorrect) tensioner and just use a longer belt. Otherwise, I will get the new factory tensioner.

As Gary says, go to Napa for better service - you may have to give the VIN to assure receiving the correct part - particularly if GM made a mid year change..Aftermarket may be a better value, but sometimes the packaging man may mess up - easy to happen...

BTW, doesn't GM use a spring loaded tensioner that can be temporarily held in a "no-pressure" position - making the belt change rather easy ???

"And there is no way to adjust the belt tension on the new tensioner by removing the pulley, unlike with my old tensioner."

I am going to jump on Earthworm's post. And the quote from your post. If there is no way to adjust how is it going to keep tension on the belt? Now different tensioners use different methods for adjustment.. Some you use your ratchet or short extension an insert it in the hole provided. On other you have to to use a box wrench or a belt tensioner bar with a socket and you use the bolt or the nut that holds the pully on to swing the tensioner to put the belt on and there are other styles. Which style do you have?

I used to be a GM partsman, I spent 6 years explaining to people why the extra money for a "Genuine GM Part" was worth it. I wish I had a print out of this thread back then.

Yes.

Hi Bob. On mine, you put a wrench over the center idler pulley bolt, and turn clockwise. this lowers the entire pulley, allowing for easy installation. Except in my case, apparently!

Thanks Tim for the advice. I agree with you. There is a problem though:

I just went to the dealer, and their tensioner is the same as the aftermarket! I bought it, and am going to compare it with the orignal one, which is a little different in design, although the old tensioner is so messed, it may not be of much help. The pulley on the GM tensioner I just bought is still pointing towards noon/1 o'clock. (I actually rode my bicycle to the dealer, 4.5 miles each way, since my car was getting too hot after a mile and a half, due to no belt on the car. :) ) So now I am at a loss.

Also, I went to Carquest, and they had a 76" belt which was way too long (it slipped right over the idler pulely without even turning it clockwise). They can order a 74" one though. I think I will need a 73" one, but that size may not be available. I am going to have to sleep on this and try to figure out what the problem is.

There is no way to adjust the degree of tension or position of the idler pulley (to account for different length belts). But tension is kept automatically by an internal spring packed in grease inside th emovable portion of the tensioner under the pulley. Turning the pulley clockwise compresses the spring, allowing you to install the belt. Then you let go, and the spring goes back to shape an dholds the tension.

You simply MUST take the old tensioner in and show it to the parts dept. There is no other way. Otherwise they HAVE to go just by the book. The book may be rong. Why? How?

Well, for example, I had a 73 Pickup and got all 4 wheel cylinders; the fronts didn't match the originals. Showed it all to the parts man who figured out the front brakes were 1972, the rear were 73. Probly the manufacturer just had a lot of '72's on hand and used em up.

Those guys usually have been at it long enough to figure out what the problem is; IF they can see the hardware.

As far as guessing the belt length -- don't. Or get 6 belts and see which fits best.

I do not know if this will work or not..
Try using some heavy string to fit over the pulleys and install this as a belt.
Then remove and measure...

I believe you will have to submit the vehicles VIN to avoid the wrong part problems...

In truth , this whole problem makes little sense - I cannot see how these things can happen...

What exactly was wrong with the old tensioner that warranted its replacement ??

Usually the pulley bearings are troublesome. New pulley assemblies, as necessary ,should be easily available...

Well, I just ran into the same problem as of yesterday. while I was driving my pulley decided to dislodge itself from my car. Luckily the belt held it in place so my car didn't over heat. I got to working on it last night and saw that the pulley, spring and insides were all outside of its casing. no grease was in there. I have decided that I'm going to attemt to replace it myself, I am so thankful that I came across this forum today. If you can offer me any suggestions, after what I have read from your last blog and this one, please do so. I'm just thinking about running down to the parts store, getting the part and comparing it to the one on my car before I decide to attempt any more work. Let me know how your belt ended up, if you have it on yet? thanks for posting, your a lifesaver!!!!

Well, After attempting to do this on my car, i soon realized that you were talking about a 91 cavalier, and it's not the same as a 98 cav. I only have one bolt holding my entire unit on. I did however run into the problem of that bolt hitting the wheelwell when I back it off all the way, hence why I haven't taken it off yet. But I found a solution. the wheelwell is double plated, and I find that with a 19mm hole drilled into the side you can pull that bolt out just fine. So right now I am attempting to do this. I have a big enough hole on the outside, and I'm working on the inside one, that one is a little harder because I don't have the use of a 1942 router on it. So you can imagine the relief when I didn't have to take my entire car apart. thanks for the learnin' though.

One more thing about the serpentine belt routing that I just thought about.

What if GM affixed the wrong routing sticker to the engine compartment ?? This could happen, and it would not be discovered until belt renewal time ...

The cheap pulleys that GM and some others insist on using is a problem, the belt itself seems to be very durable.
The Saab forum people say to change the belt AND the pulleys every 50,000 miles or so. Via DIY it is an easy 1 to 2 hour task using about $80 in parts. The dealer price for this is shockingly high !!

so i just had to replace the alternator on a 99 cav which was a breeze.....unfortunately gettin the serpentine belt back on is bein a huge pain.....any tips? im sure ive got everything routed correctly, it just seems like the tensioner doesnt actually give enough slack, it gives what, 1/2"-1" when loose?

The tensioner assembly pivots, and can be easily locked in place allowing for an easy belt change or re-installation - this, I guess is a newer GM design for the mid 90s.
No wrench is placed on a pulley, this would do no good..
Assure that the new alternator has the correct sized pulley - one usually has to use the old one anyway...
As I recall, the tensioner should be able to be pulled about 2", then it is locked in place with a 4 or 5 mm Allen key.. And it does take a good bit of strength to do this.
If a man cannot move the tensioner the 2" or so, then I 'd say that something serious is wrong...

FWIW - Just changed the tensioner on my 1991 2.2L Cavalier.

Step 1: Disconnect Battery.

Step 2: Remove Belt (15mm wrench clockwise to remove tension)

Step 3: Remove Power steering pump. Remove small bolt on back side of power steering pump (next to hose with clamp)Use a box-end wrench or one of those ratchet box-end wrenches. Next, there are 3 bolts in the front behind the pulley(13mm). There are holes in the pulley specifically for the purpose of removing these bolts. I used a magnet to pull the bolts out after loostened. You should now be able to rock the top of the pump toward the firewall. Be careful to not break the plastic top. If you have to pry it, do it on the metal part.

Step 4: Remove alternator. Remove all bolts holding the alternator in place. It should just be laying there (Upper bracket removed).

Step 5: Remove belt tensioner assembly plate. Remove four 15mm bolts that hold the plate on the engine block. Mine were on pretty tight so I had to use a breaker bar to get em off.

Re-assembly:

Step 6: Compare new tensioner assembly with old one. They should match. Attach plate to engine block with four 15mm bolts. Make sure they're tight. You don't want this to come loose.

Step 7: Re-align power steering pump to 3 holes in tensioner plate and screw in the 3 bolts (don't tighten yet). Now here's the hard part - carefully take the small bolt that goes in the back of the pump assembly and get it started with your fingers (the 2 holes should be aligned). Tighten all 4 bolts.

Step 8: Alternator - Re-install the long bolt and nut that goes in the bottom of the alternator but don't tighten. You may have to loosen the lower alternator bracket so the two holes align. Let the alternator swing towards the engine. This will make it easier to get the belt on.

Step 9: Serpentine belt install. If new belt, make sure it's the same length as the old one. Route the belt like the diagram sticker. The alternator is the last pulley it will go over. If you can get someone to help you here, it's a lot easier. Turn the 15mm bolt on the tensioner pulley clockwise until there's enough slack to slip the belt over the alternator pulley. While keeping the tension off the pulley, replace the other 2 bolts/upper alternator bracket. Slowly let the the tensioner spring back. Replace and tighten the rest of the alternator/bracket bolts.

Have big problem...replace crankshaft pulley then original belt way too tight to fit on..it's a mazda 626 lx v6 1998...belt connects alternator ..Ac...and crankshaft pulley. . Belt short by about 1 1/2"

I'm stuck for 2 days ...dont know what next to do..need some help

The belt I used GATES K050398

The information I have is for the '82 through '89 Cavaliers. Those do not have a belt tensioner. Those may have an idler. The belt is tensioned by sliding the alternator in its mount and locking the bolts. To replace the belt, loosen the alternator bolts/nuts and slide the alternator down. These bolts are in slotted holes. Put on the new belt and then tighten the belt by sliding the alternator upwards and tighten the bolts. A pry bar is useful for prying the alternator to snug the belt while tightening the alternator bolts. Be careful of what you pry against.

Thanks for your advice...I checked slotted holes but there was none the only way to adjust belt is through tensioner.

My repair manual covered the '81 through '89 models. Yours is a '91; There must have been a change in belting detail and I am assuming we are talking about the accessory belt and not a timing belt. I believe the '82 through '89 engines had timing chains rather than a timing belt.

One some old vehicles that I have owned, the accessory belt adjustment was by moving the power steering pump.

Was more than one engine offered for your model? That can create parts mix up.

If you truly have a tensioner, there may be a way to cock the tension idler arm during belt installation. Look for a pair of matching holes in the idler arm and the base. These holes do not match up with the tensioner relaxed, but if the tension arm is rotated against the spring tension, the holes may match up. If these holes are present, mount the tensioner to the engine, apply a suitable tool to rotate the arm and insert a steel pin through the holes. Be very careful working around this thing when it is cocked. There is enough stored energy in the spring to do serious damage to parts and human hands. After the belt is on place, remove the pin and gently allow the tension idle wheel to come in contact wit the belt.