Okay, got the tensioner replaced, and the noise/vibration is gone!
I noted that we don't currently have a writeup on how to replace a belt tensioner in techinfo, so for the hell of it, I thought I'd write up one for future members to reference off of. Hope this helps someone later on.
The unsuspecting victim:
Earlier in this thread I mentioned the brands I'd rather avoid, including Gates and Dayco. However I decided to do research on both just to make an informed decision on what would be the best and most cost effective tensioner to get for my car.
The Dayco was awful tempting. It was the cheapest, and even more so considering I would have gotten $10 off with the current Advance Auto Parts promotion. However, upon looking at the part, I noted that it appears to be an EXACT copy of the Duralast tensioner I had on the car already that failed prematurely. Be warned that I believe that Duralast tensioners are made by Dayco, and therefore are to be avoided. These tensioners have no tension indicators on them and fail prematurely.
However I read that several people liked Gates tensioners, and upon looking at one it appeared to be an exact OE copy. It seems, as a whole, to be very solid and well made. It even came with a brand new coolant elbow in the box. How convenient is that? The unit is made in Canada rather than China which is a huge plus. I bought my Gates tensioner at O'Reilly's Auto Parts for about $98 before tax. I would have preferred AC Delco naturally, but I couldn't wait for Rock Auto to ship it to me. I do believe Gates to be an acceptable substitute though. Here is my Gates unit with included coolant elbow:
I looked it over well, and it gets my approval. Note that it appears to be an OE copy and includes the tension indicator marks.
Here is a list of all that you will need to complete this project:
Ramps or jackstands
Coolant (1 gallon of pure antifreeze is all you will need more than likely)
Tensioner and a spare coolant elbow
Pliers (or appropriately sized wrench for your negative battery terminal)
15mm wrench
8mm wrench or socket
10mm socket
1/2" socket
short extension
ratchet
flathead screwdriver
funnel
bucket to catch coolant
...and most importantly, beer of your choice and something to keep said beer cool in.
To avoid burns, it is best to do this when the engine is cold.
First, drive your car up on ramps or jack the car up and place it securely on jackstands.
Next you will need to drain the coolant. Remove the splash shield first (flat plastic guard directly behind the airdam and under the radiator). Then locate the petcock, or drain plug for the radiator. The petcock is located on the driver's side of the radiator, near the bottom. Have a bucket ready to catch the coolant (it will fall directly under the petcock) and turn the petcock counterclockwise to allow the coolant to drain. In the following picture, I am holding the petcock with my hand to give you an idea of it's location.
Allow the coolant to drain. Remove the radiator cap to allow the coolant to drain more quickly.
Leave the petcock open and allow the cooling system to drain. While it's draining, you can do just about everything else. Begin by disconnecting the negative battery terminal. I had to use pliers because I couldn't find the appropriate sized wrench for the job (I believe mine is some increment of thirtysecondths that I don't have) but it is recommended to use a box end wrench for the job.
Next remove the accessory belt. Place a 15mm wrench on the nut at the center of the tensioner pulley, and push hard counterclockwise back towards the firewall. The pulley will give some slack and the belt can slide off.
No belt!
Next, use a 1/2" socket to remove the alternator power wire and tuck it safely out of the way.
Use the same socket to remove the two bolts and one nut on the passenger's side of the alternator. One of these bolts is under the tensioner pulley.
Now you need to remove the alternator bracket with the same 1/2" socket. There is a nut under the coil packs. Due to space constraints, I used a 13mm wrench to remove this nut.
The bracket can now be removed. Removing this bracket will expose another 1/2" bolt that will need to be removed. Remove it. Lastly, remove this final bolt pictured. You will need a 10mm socket for this one.
The alternator can now be pulled free.
Don't pull too hard though; you still need to remove this electrical connector before the alternator can be completely removed.
Now you're down to the tensioner itself. Only four more bolts to go. Look at your new tensioner, the holes for the mounting bolts are clearly visible. All are 1/2". You will have two left, the others were removed during the removal of the alternator. Feel for these remaining two; they are along the bottom of the tensioner, one in the middle and one in the back towards the firewall.
The remaining two bolts that need to be removed are 8mm bolts holding on the heater core hoses. Remove these bolts and pull the coolant hoses out of the sockets in the tensioner. Some coolant may spill.
Everything free, the tensioner is now ready to be removed:
Pull on the tensioner from the front and rear carefully. Try not to break the coolant elbow. If you do it's okay, as you've already bought a spare (yes, you have).
Tensioner removed:
My parts carnage. Note that I have grouped bolts with the parts they go with:
The beers are stacking up.
I managed not to break my coolant elbow for about the fourth time in a row. However, seeing as I have two spares lying around, I decided to go ahead and replace it. The O-rings looked kind of nasty anyway.
Here's the new tensioner with the new coolant elbow in place.
There are two coolant ports that have to be lined up to go in the engine. One is built into the tensioner, and is directly under the tensioner pulley. The other is the coolant elbow itself. Look carefully and you will find the holes both of these outlets go into on the engine. The coolant elbow goes into the lower intake manifold. Once you have lined everything up, pop it in place securely, and replace the two (and only two) mounting bolts that you removed from the tensioner earlier. Then, replace the heater hoses and the 8mm bolts holding them in place.
Reattatch the alternator, starting with the electrical connector that you removed right before taking the alternator out of the engine bay. Keep the bolts loose until you have it properly aligned, then tighten them all securely. Be sure to reattach the alternator bracket and alternator power wire. Once you have done that, you can grab your 15mm wrench and put the belt back on. Be sure to follow the proper belt routing diagram.
Close the petcock on the radiator by turning it clockwise until it is good and tight, but don't over do it as it is plastic. Then, follow the coolant refill procedure as specified here in techinfo (
http://www.pontiacbonnevilleclub.com/fo ... f=53&t=159 )
Be sure to safely dispose of your old coolant.
All put back together, filled up, and running great!
I hadn't done one of these in a while, so altogether it was a four beer job, or about 1.5-2 hours.

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