Replacing Chevy Belt Tensioner

mileena3September 23, 2005

Hey everyone,

I have a 91 Chevy Cavalier 4-door sedan (4 cylinder) with 190,000 miles on it. All of a sudden, after starting the car, I heard a loud squealing. I checked under the hood, and the serpentine belt is very slack. I used a 15 mm wrench to adjust the idler pulley upwards, to make the belt tight, but merely pressing down on the belt with my hand makes the pulley go back down again, and the belt becomes loose. The belt itself appears fine. I guess I need a new belt tensioner??

Just an FYI: on my car, the belt connects the crankshaft pulley, water pump, alternator, power steering pump, and idler pulley. The idler pulley is held in place by one 15 mm bold, and it is supposed to tension the belt

automatically. Up to now, it has.

After consulting the offical Chevy shop manual, it appears that replacing the tensioner is an easy fix. Just remove the belt, PS pump, and loosen two alternator bolts. I have done quite a bit of work on my car myself, such as replacing tie rod ends, rear springs, valve cover gasket, water pump, radiator, brake calipers, brake lines, etc., so this does not worry me.

I am worried, however, that the PS pulley have to be removed to access the PS pump bolts. The pulley is rather large. It's dark out now, so I can't tell for sure, but it appears I will have to remove the pulley to access the bolts?? Can I still leave the hoses attached so I don't have to bleed?

Is there a temp fix I can use just to make my car driveable, so I can get to the parts store?

I suppose if all the pulleys suddenly stopped turning while driving, the only harm would be the coolant not circulating, and the consequent overheating, right? As well as the draining of the battery, although I have a professional charger for that.

Thanks for any help!


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Another thing I am wondering is this:

The manual says never apply more than 30 lb. ft of torque when turning the idler pulley bolt to remove or install the serpentine belt. But how does one know how much torque one is applying? I always use a 15 mm box-end wrench. It is almost impossible to fit a socket/ratchet over the bolt, given the wheel well inner body interferes. I once got a 1/4" ratchet/socket over the bolt, but it was hard to get off.

Also, I notice there is a groove in the belt tensioner from the belt apparently rubbing against it. But the belt itself is fine. This has been going on for a few years now, and never happened before. I am wondering if I somehow caused this problem, because:

a) One of the bracket bolts has always been missing from my alternator set up. When I replaced my alternator a few years ago, I put that bolt in, but then there was another place that had previously had a bolt where I was no longer able to get the bolt in. But there are enough other bolts holding it in place where I feel it is fine. You can't even budge the alternator by pushing it.

b) In 1999, I removed the idler tensioner pulley just for the hell of it, as I replaced my water pump. I reinstalled it, and torqued it to spec. I hope I wasn't supposed to line anything up!?

    Bookmark   September 24, 2005 at 3:10AM
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I do not know if this GM design is similar or the same as the one used on the '94 -'98 Saab 900 or not..
I suspect that it is, both are GM designs...
Here, to release the serpentine belt tension, one uses a 1/2" lever to move the spring loaded tensioner and a 6 mm pin to hold the unit..
The pulley bearings are know to wear out - even to the point of being replaced every 50,000 miles !
Why not just pull the whole tensioner and examine it.

If the power steering pulley is actually in the way ( but aren't there access hole in this pulley?) it may have to be removed.
I think the PS pump can be lifted out of the way using Bungee cords, no need to disconnect anything....

    Bookmark   September 24, 2005 at 12:03PM
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Thanks earthworm! I am replacing the entire belt tensioner, but have to remove the PS pump first to get it off.

The only thing I am having trouble with now is getting one last bolt off that holds the power steering pump, which you have to remove to remove the tensioner. It is in the back of the pump, on the opposite side where the pulley is.

In the meantime, I have removed so much stuff just to be able to get this tensioner off, it is ridiculous:

PCV valve hose
Canister hose/line
Both PS pump hoses (I did not want to have to do that!)
Coolant overflow tank
Two alternator bolts
Idler pulley

What should be an easy job has turned out to be a big one!

Now back to that final PS pump bolt: the problem is it is almost impossible
to access:

a) On the side of the pump facing the front of the car is the cylinder head, which prevents a wrench from fitting.

b) On the side opposite the PS pump pulley, 1/2" away there is a vertical
heater hose attached to the bottom of the head/intake manifold, and there is one of those annoying spring-type clamps holding it on. The problem is access is so tight, it is impossible to maneuver pliers in there from any
angle, including those special pliers for removing the spring-type clamps. And the prongs of the clamp are only 1/4" or so from the wall of the PS pump, and deep down from the top. And one of the prongs is under the manifold! (The problem is I cannot get to the PS pump bolt from the top
unless I remove the heater hose. But I cannot remove the heater hose unless I remove the PS pump! Catch-22. The manufacturer must have assembled the intake manifold/heater hose together as a unit, without regard to where the
spring-clamp faced???)

c) And finally, if I try to access the PS pump from under the car, it will be very hard, as it is high up, with almost no room to fit my hand in around the exhaust pipe, oil filter, cross-member, etc. Although I admit I have not
tried this yet.

d) On the side of the PS pump facing the firewall, there is a bracket attached to the PS pump holder bracket that makes accessing the final PS pump bolt hard. I could disconnect this bracket (I have already disconnected one side at the PS pump holder bracket), but here is the weird part: no
wrench will fit over the nut holding the other end of the bracket in place! I have tried 10, 11, 12, and 13 mm. I have also tried 7/16" and 1/2". 11 and 12 mm seem too big. 10 is too small. Same with 7/16" and 1/2". The problem is I really cannot see the nut to see what the problem is, since the nut is over a vertical stud attached to the bottom of the intake manifold, and the nut is facing down, towards the ground. I assume it is a hex nut I think it feels like one, but it is hard to completely feel, since I cannot get my fingers all the way around it. You know what? It looks like one of those nut caps that my car uses to hold the thermostat housing in place: capped hex nut, with a star shaped design protruding out on the cap part. Really weird. But it is supposed to be torqued 48 lb. ft., which seems like a lot for a small nut, although it is ultimately connected to an engine mount.

If I only could get that nut and bracket out of the way, then I would be able to turn a wrench to get the final PS pump bolt out.

Another problem is, assuming I can find the right size wrench or socket, this nut is torqued to around 48 lb. ft., and there is limited access to get a 3/8" ratchet in there to loosen it. A 1/4" ratchet will not have enough torque. And maybe not even a 10 mm wrench. Perhaps I will have to remove the blower motor too.

I just don't know what to do.


    Bookmark   September 24, 2005 at 10:11PM
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most autoparts stores sell a new type of socket/ratchet combo that has sockets that mount into the ratchet instead of on a 3/8 or 1/4 square drive, theese will give you the tourque you need, and still clear tight spots, as only the depth of the socket itself needs to fit into the space.
wow I can't belive something that fails as often as a tentioner needs the PS Pump removed to replace. what a crappy design! make sure it is true before you go to all the trouble to get the PS pump out.

    Bookmark   September 24, 2005 at 10:20PM
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Thanks John! I will keep an eye out for those special ratchets with sockets.

I actually just installed the new belt tensioner. I was able
to access that one PS pump bolt from a downward-back angle. It was a pain aligning the tensioner plate with 9 different bolt holes, but I finally did it! Only one problem now: the belt won't fit on, but I will start a new thread about that.

    Bookmark   September 25, 2005 at 5:47AM
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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.


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.

Step 10: Re-connect battery

    Bookmark   April 16, 2010 at 10:21PM
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