Write-Up: Replacing Belt Tensioner Pulley (Series I)

Ok, my shop manual is not giving me squat for the info I need. What is the pulley that sits between the tensioners called? It is the pulley that has the ribbed inner and smooth outer. The outer has seized on me, and the only thing I get from parts stores is tensioners. I assumed it was just an idler pulley.
Anyone help me out?

Look here, this might be of some help.
https://rivperformance.editboard.com/series-ii-engine-transmission-f4/write-up-replacing-belts-and-pulleys-t725.htm

Sadly, this Riv does not have the same as I have. Looking at mine facing towards the driver's side, the top tensioner is to the right, the lower one is to the left. If you drew a line from one to the other you would cross over the pulley in question.

The S1 is different, but I thought the idlers were still the same idlers. Can you post a picture?

If you look between the water pump and the power steering pulleys, that is what I need to replace. Specifically the smooth part, but I will do both. You see that it has a belt connected on the back, and the smooth front does not have a belt on it.
I am assuming, and this picture helps, that I just need to break the bolt in the center, replace the pulleys (with new bearings included) and torque it back down.
I am concerned that the pulley seized. Hope all comes apart fine.

It sounds right. Dayco has a good variety of pullies, and you should be able to replace the tensioner pulley without replacing the entire tensioner.

Have you tried NAPA?

Well, I have no need to replace a tensioner or tensioner pulley. My issue is with the 'idler' pulley that sits between the power steering and the water pump.
Back at the office where the car sits, and replaced the front pulley. That spins nice. The back does not spin very well. With no belts on it, should I be able to get a few revolutions just by spinning it with my fingers, or should it not spin much at all?

It should spin freely with no belt on it.

I'd replace them both if i were you. When I needed to do one of the "idler" pullys I just did them all, tensioners too. For the idler pulleys I just went to NAPA and said I wanted both Idler pullies for the car...

Have you tried to remove it yet? Should be able to get a GM part # off it, and cross reference it on Dayco and Gates sites.

If you go to the gm dealership and ask they will give you your answer.

With my luck when it happened to me, GM was the only place that knew didly squat.

They sell it as a set, it includes the bolt and both pulleys, and it costs around 75$

Dayco lists this for a 95 SC Riv:

1995 BUICK RIVIERA - V6 3.8L 231ci GAS FI S 1


Belts / Tensioners / Pulleys
Part Number Description
5060605 Alt., P.S. & Idler
5060860 W.P., Comp. & SC
89007 Idler Pulley (Smooth)
89007 Tensioner Pulley (Alt. & P.S.)
89007 Tensioner Pulley (SC Drive)
89375 Automatic Belt Tensioner (SC Drive)
89376 Automatic Belt Tensioner (Alt. & P.S.)

Jerry, has that engine been sitting a while?

Albertj

Mine has not. The picture is just something I found on the net.
Good news for me, got the pulleys and belts replaced. Fired it up, and expected to chuck a belt from the get go (this is how this car treats me)
Car ran, and all is looking good for that part. Now I still have the matter of a coolant leak to find.

You may want to search this site for info about coolant leaks involving the intake manifold and coolant connections to the engine.

My guess is when you put the new pulleys on you got them on right and in line - with that, don't assume the 3800 engine is going to create drama for you just for fun. It is a workhorse that can be a racehorse; it is not a diva.

About those other pullies. You currently have no need, per se, to replace the other pullies. However, if you do, you will avoid the drama of sudden pulley failure. The plastic pullies work well but when they fail they frag, they most often rip the belts and send bits of rubber and plastic everywhere. I mean, they usually fail gracefully... when my tensioner pulley for the supercharger belt went, the car was still driveable although it made a big mess, part of the mess snagged teh idler pulley (taking it out too) and shredded the belt.

Anyway - as long as you are in there please turn them all by hand and if you feel any binding at all then you ought to go ahead and replace that sucker. I suspect that a little bit of binding makes heat that dramatically speeds up the pulley's failure. Oh yeah, a couple things. One - if you go to the dealer don't be surprised if the tensioner or idler pulies for the blower are steel instead of plastic. The steel has a small performance penalty and a big durability bonus. Also, so that the new ones seat correctly, check for plastic flash near the seating surfaces and trim it off before you install.

Happy wrenching...

Albertj

The newer plastic replacement pulleys from Dayco and Gates are a huge improvement in quality from the crappy OEM pulleys that GM stuck us with. I seem to recall both mfgrs telling me they will last 5X longer than the OEM plastic ones. I don't think you can go wrong with either steel, or new plastic ones.

Ok, new development. Got the pulleys on fine not long after the initial posting. replaced the belts, and for a time life was good. Last week, in the dead of night, in the worst possible spot, the SC belt just came off. With no other option, I had it towed to a shop where the owner is a Riv fanatic. Just got it back today (was sick) and he told me that he could not find any reason for it happening. He took straightedges to the pulleys, and they are lined just perfectly. No wobble in any pulleys. Belts are fine. He said the only thing he could think of would be an external force, which he cannot see, and has never seen.
I hope this is not a sign of things to come.

Is the tensioner good? It should provide a good deal of resistance when you try to manually move it thru it's range. Seems very odd that it would come off with no apparent signs of a reason. Plus your mechanic says it's all aligned properly. Does the belt feel tight when you push down on it?

I would have suggested the belt may have been off by a rib on the pulleys, but that would likely have caused problems much sooner.

Well since there does not seem to be one of these I will start a thread. I had a 1963 Olds F-85 coupe a billion years ago which was the last car I owned that I worked on at all.

Here is a poor video of my current engine at idle, I was hoping you could hear the chirping but you can not.

https://www.youtube.com/watch?v=R4h4rpQVKfw

Here is the part from O'Reilly which has it in stock near my location.

Link



I will add pics and further description after I finish. That is if I don't blow up in the process.

OK - Just finished replacing the Pulley, Lucky for all of you I made plenty of mistakes from you to learn from. For the experianced mechanics here I should provide plenty of commic relief.

I watched a video on youtube of some one replacing belts that sent me a little in the wrong direction right from the start. In this first picture you see that I am loosening the mounting nut for the pulley, my first mistake . This nut is of course the same way you relieve tension from the belts.


Here is the bolt and dust cover. The gates replacement indicated that you did not need a dust cover and to check operation if you choose to use one. I used it and there is plenty of clearance.



This is what it looks like with the bolt and dustcover off:



I was able to push the tensioner over enough to allow me to slide off and put on a new pulley with the belt in place. This would have been easier of course if I just dropped the belt put on the pulley and then used the mounting bolt to relieve the tension and rerun the belt.

Here is the completed repair:


The sad ending to the story is that my chirping is still there, it must be the SC connector. Not sure if I will attempt that myself or buy the part and have the AC/Delco mechanic in town do it.

your chirping might not be the SC, it might be the alternator bearing.

Please consider slipping the belts off, both of them, then turning all the pullies by hand. Slowly so you can feel if there is any grittiness or binding - sure sign of a going-bad pulley or device (alternator for instance). Whether or not you find a gritty one, next thing to do is as much as you can, turn the pullies fast.

I suspect you will find the chirper. You may find the chirping is the belt itelf, although it's not usually the case that the ribbed serpentine belts make that kind of self-noise. I had one once that did, turned out the belt had become glazed. Go figure.

Good luck.

Albertj

1998 Riv wrote:

Dayco lists this for a 95 SC Riv:

1995 BUICK RIVIERA - V6 3.8L 231ci GAS FI S 1


Belts / Tensioners / Pulleys
Part Number Description
5060605 Alt., P.S. & Idler
5060860 W.P., Comp. & SC
89007 Idler Pulley (Smooth)
89007 Tensioner Pulley (Alt. & P.S.)
89007 Tensioner Pulley (SC Drive)
89375 Automatic Belt Tensioner (SC Drive)
89376 Automatic Belt Tensioner (Alt. & P.S.)

My 95 Riviera only has 43k miles, but I'm certain that the pulleys are all original. So I'm going to change them all out while I'm in there since the belts are very old as well and splitting.

I already have the following belts:

Dayco 5060860
Dayco 5060605


I'm more interested in reliability than absolute performance, so if the consensus is that the steel pulleys are more durable (but may exhibit a little more drag) I'll go with them.

It appears from the diagram for the 95 Riviera that there are four pulleys that need replacement.


Based on the experience here, can someone verify:

1) How many and what P/N metal pulleys are recommended for each location? It sounds like I need three 89007 "smooth" equivalent pulleys. I think I'll go with the metal ones for these. Can this be confirmed?


2) It looks like one pulley (ribbed) may not be available in metal? If so, what manufacturer and P/N is recommended?

3) Which if any of the pulley locations uses a reverse threaded bolt?

4) Is there any recommended method to hold the tensioner still while loosening/tightening the pulley bolt? Is it a non-issue?


Hoping to learn the most durable part selection for the 95 pulleys based on what everyone here has learned over the years. I'd like to not change them again for another 100k miles

Thanks!
Al

I still maintain - turn the pullies by hand. If no squeak, bind or grind, I'd leave 'em - except the other thing is to try to tap the pulley off-axis with a rubber mallet or heel of your hand. A steel pulley with a weak bearing will go off axis without much of a whack. A plastic one would have already broken from the heat of the bad bearing.

As for the pullies you see, best bet is pull up the RockAuto.Com web site, they are all listed with pictures. Stick with a good name like Dayco or Gates and you'll be OK. Summit Racing carries them too, I think the DAyco ribbed metal is 89051 but Don't Quote Me - Check For Yourself.

Thanks, I agree witht the "ain't broke don't fix it rule" generally, but this car has sat for 4 years and I'm almost certain the pulleys are all original 18 year old pieces. So since I'm already changing the belts, I thought I'd do a little preventative maintenance and get them all done since the pulleys are so cheap.

Interestingly Dayco doesn't seem to have a steel ribbed pulley for the 95 (Series I) engine. The 89051 is apparently only for 96+. Too bad.

I guess I'll get the Gates Part # 38009 DriveAlign Premium OE Pulley; Thermoplastic V-Ribbed 6 Grooved (76mm x 17mm x 25mm).

It seems to be popular according to RockAuto, along with the DAYCO Part # 89007 More Info {#89007FN} Drive Belt Idler Pulley; 76mm x 17mm Flat Steel, 31mm wide.

At least these are really cheap. Glad to see something is still cheap these days!


So to be clear:

1) I'll need three of the smooth Dayco 89007, true?
2) I'll need one of the ribbed Gates 38009, true?

...that's it, correct?


Any tips on if any of the bolts in the three locations are reverse so I don't go breaking any off?

Thanks!
Al


P.S.

Yes, I have a Service Manaual set on the way, and I'll also be geting a code reader, but don't have them yet. But I'd like to get these parts on the way so I can do the work this coming weekend.

IIRC, none of the pulley bolts on the Series one are left hand thread.