Can anybody tell me really quick how to release the tension on the serpentine belt? On the Grand Prix there'* no engine mount going through the belt path, so I should be able to simply release the tensioner and slip the old belt off, slip the new belt on, and re-apply tension to the tensioner. I've looked at it and I don't see how it'* supposed to move.

Can anybody either tell me how to do it, or show me a diagram, or something?
Much thanks in advance!

Oy, never mind.

Instructions:
The idler pulley is the tensioner for the serpentine belt. To loosen it, do the following... - Notice the bolt in the centre of the idler pulley. Find the appropriate socket. - Using your rachet (set to loosen) put the socket on the bolt so that the rachet handle is pointing towards the windsheild. - Push down on the rachet handle. The tensioner will give slack to the belt. (careful because it is under spring tension) - While holding the tensioner down slip the belt off. Gently allow the tensioner to spring back slowly until it stops.

If I remember correctly it was an 18mm socket
Also I found it was easier using a Breaker Bar, rather than Ratchet, to pull back on the Tensioner. Of course your results will vary.

It was 15mm, and it'* a great help if you remove the two 10mm snapnuts that hold the coolant overflow tank to the inside fenderwall, and move it out of the way. (You can leave the hose connected to it.)

I'd recommend a breaker bar too, but my 15mm socket is 1/4" drive and my breaker bar is 1/2" drive, so I'd need a 1/2" drive to 3/8" drive adapter coupled with a 3/8" drive to 1/4" drive adapter on the breaker bar in addition to the socket, and that wasn't going to fit.

I used a slightly more dangerous method of using a combination wrench on it, closed end around the pulley bolt, open end interlocked into the closed end of the largest combination wrench I own (the old "interlock-two-combination-wrenches-for-more-leverage" trick) and used that to un-tension the belt. Replacing the belt was a simple matter of slipping the new one on and flexing the tensioner again to get the belt over the alternator pulley.

It'* a little more dangerous because the spring on the tensioner pulley is very strong, and it took a lot of force on the interlocked combination wrenches. If they slipped, they would have gone flying into my face or something. So I was just really careful about it.

In the end I'll wind up going to Sears and buying some 3/8" drive metric sockets. I already have a set, but they're deep-well sockets, which also wouldn't fit into the cramped space to get to the tensioner pulley.

Job took less than five minutes. I wish our Bonnevilles didn't have that engine mount going through the belt path.

And also, just for the record, I'm officially a big fan of the GoodYear Gatorback belts, after having Delco belts crack all over within a year. You can still drive no problem with cracks, but it'* one of those things that will just annoy me until I make it right.

But for anyone with a Grand Prix, a breaker bar, and a 15mm socket, definitely replace your own belt, don't pay anybody else to do it, it'* a piece of cake.

Or a 3/8 ratchet and a 15mm socket and a 10mm wrench or socket. Thats always been enough for me, and I'm not a strong guy. Accessory belts on l36 gp'* are a piece of cake.

Having the correct tools will make any job 10 times easier. Also FWIW anytime you are using the reducers (like 1/2 drive to 3/8 or 3/8 to 1/4 or whatever) make sure you're not using them to put more torque on it. They are very weak and I break them every time I try that. I only use them when I can't get in there with that type of ratchet or something like that....or if I don't have a 1/4" ratchet on hand or something like that.