Pulley Grinding on Engine Mount

So yesterday my Riviera made this weird grinding noise under the hood. I checked it out when I got home and saw that one of the supercharger pulleys was grinding on the engine mount. Any possible reason for this, and how much it might cost to get fixed? It still runs and drives but when it goes into gear or accelerates it makes a horrible grinding sound. If it's in park and revved up it makes no noise. Help?!?!

Sounds like the transmission mount or the forward motor mount is worn out/broken.

ouch...Yeah, i'd be putting that bad baby in gear and kinda brake torque a little bit while having someone watch to see how much that motor moves.

Seems likely. There's very little clearance between that lower pulley and the mount.

1998 Riv wrote:

Seems likely. There's very little clearance between that lower pulley and the mount.

...and the mounts are not very stout in the first place.

Tyre, why not have a look at those mounts, maybe take some snapshots of them, and report back.

albertj wrote:

Sounds like the transmission mount or the forward motor mount is worn out/broken.

really no other reason why the pulleys would come in contact with that bracket unless the mount on the passenger side is blown out.....

Abaddon wrote:

albertj wrote:

Sounds like the transmission mount or the forward motor mount is worn out/broken.

really no other reason why the pulleys would come in contact with that bracket unless the mount on the passenger side is blown out.....

Exactly, is it the w/p or one of the s/c idlers?

here are some pictures, hope this can help

In the bottom photo it seems to me that the front motor mount is not sitting normal. The whole engine seems to be leaning back.

The mounts you need to check are under the car. One is the forward lower mount not far from the radiator side of the transaxle bellhousing and the other is often called a transmission mount (it bolts to the other side of bellhousing) and it is up under approximately the middle.

There are other pix posted to this site that show all the mounts in place as part of a writeup about replacing motor mounts.

My guess is your transmission mount has failed and the forward motor mount if not failed is quite weak.

You are going to be unhappy when you see how lightweight they are in the first place.

You may well have to replace the can-shaped mount that you can see in the pictures if it has stretched out enough. Len Rapkins posted that he got a park avenue mount and swapped the insert by bending the metal tabs out on both and swapping cores... sounds OK to me.

But yeah basically you have weak/dead motor mounts and the whole engine is canted. It's a DIY job too because at the dealer it will run close to a grand parts and labor for a job you can do yourself for under I think $200 or $150 I forget what Len eventually spent.

You should also double check and make sure the tensioner pulley is the right size. There is an outside chance that someone installed the larger one there. Riv has 2 sizes of idler pulleys, smaller ones all except the one that goes under the pass side motor mount, that is a bigger one. Reason I say that is I notice your SC belt is a nearly new poly-V and the OE pullies are all plastic. So the tensioner pulley should be the same size as the plastic idler pulley to its right. Look on your hood insulation for damage. I wonder if PO had a belt shred and it was not fixed right in the first place. Reason I mention that is that I know firsthand that some parts books show the wrong pulley, fortunately I was not the one repairing my car at the time, the dealer was, and they noted the problem on installation and I think got the right pulley from a nearby Ford dealer.

Yeah, you have some wrenching to do.

Actually, looking at those pics, it's a possibility that the locating pins for that tensioner may have broken? This would cause the tensioner to turn and hit that bracket. That mount pictured, as well as the bracket don't appear to have really any stress on them. If all other mounts were blown out, you'd think that that mount would be on a giant angle.

And what's with the hammer marks on the Water Pump?!?!

Somebody has obviously been in there before....the nut on that bracket stud is new.......

OK Tyre, what's up with your Riv?
that is, can you confirm Abaddon's suspicion about the WP?

Put another way please tell us what else is going on. You mention your riv was recently repainted.

Why?

@ Abaddon I still think the mounts are weak. I think we'd have to be there to see unless Tyre cares to crawl under and take some snaps. We will see.

I have no idea what's going on with the water pump. and my signature is outdated but it was painted almost three years ago by Shieb Paint & body. too bad they no longer franchise operated b/c the paint warranty is now void.

The belts were replaced about a year ago because one of them popped off while driving. The passenger mount was taken off to put them on.
The engine still leaks oil in certain places, the seals need to be replaced.
Now the s/c pulley grinds on the mount, I drove it today and it wasn't as bad. You hear it when you start it up and when you accelerate or if you hit a bump, and when the car goes off. if it idles while in drive, the steering wheel shakes so i'm assuming it would be a weak mount somewhere.

http://twitpic.com/4g547j
http://twitpic.com/4g55f4

Got it.

The installation of the passenger mount should be checked as well.

the apparent hammer marks on the WP are probably from the work to replace the belts... just a guess, I think they are marks from the end of the wrench.

FYI Actually you *do not* need to remove the mount to replace the belts, if you have the revised mount (most Rivs do after late '96 build date I think). You take the front pas side wheel off then you bend back the fender liner and take the bolt and ferrule out of the bottom right corner of the mount. There is a write up on that on this site, but it is *not* in any service manual that I know of.

In summary there seem to be 3 things (no particular order)

1 - slip the belt off the tensioner and check the tensioner to see if it is still mounted right. If those locating pins are broken you will be able to move the tensioner about somewhat where it's mounted. It should not move at all. And anyway, with your mileage if you have not replaced the tensioner yet, you are (over)due.

2 - usually the transmission mount is pretty much goners by 80,000 miles. The other mounts follow. Unless you have already, more than likely you need to replace them. Think of it this way - you have a 240 horsepower engine held in place against its torque by about 8-10 cubic inches of rubber that gets stretched and compressed a lot. They just don't last long. And Abaddon I could be wrong but the rubber at the core of the pass side mount looks checked in the picture. Maybe that's just a shadow.

3 - I would measure the two pulleys on the tensioner. They should be about (within 1/8" of so) the same size. Actually, if you replace the tensioner they come with new (correct) pulleys so I guess it does not really matter.

Let us know what you do/decide... you have a nice looking Riv and with a little mechanical TLC it will run better than it looks.

albertj wrote:

Got it.

The installation of the passenger mount should be checked as well.

the apparent hammer marks on the WP are probably from the work to replace the belts... just a guess, I think they are marks from the end of the wrench.

FYI Actually you *do not* need to remove the mount to replace the belts, if you have the revised mount (most Rivs do after late '96 build date I think). You take the front pas side wheel off then you bend back the fender liner and take the bolt and ferrule out of the bottom right corner of the mount. There is a write up on that on this site, but it is *not* in any service manual that I know of.

In summary there seem to be 3 things (no particular order)

1 - slip the belt off the tensioner and check the tensioner to see if it is still mounted right. If those locating pins are broken you will be able to move the tensioner about somewhat where it's mounted. It should not move at all. And anyway, with your mileage if you have not replaced the tensioner yet, you are (over)due.

2 - usually the transmission mount is pretty much goners by 80,000 miles. The other mounts follow. Unless you have already, more than likely you need to replace them. Think of it this way - you have a 240 horsepower engine held in place against its torque by about 8-10 cubic inches of rubber that gets stretched and compressed a lot. They just don't last long. And Abaddon I could be wrong but the rubber at the core of the pass side mount looks checked in the picture. Maybe that's just a shadow.

3 - I would measure the two pulleys on the tensioner. They should be about (within 1/8" of so) the same size. Actually, if you replace the tensioner they come with new (correct) pulleys so I guess it does not really matter.

Let us know what you do/decide... you have a nice looking Riv and with a little mechanical TLC it will run better than it looks.

Albert, I agree. We arent there to see it physically, so who knows. That rear mount on the driver's side would have to be really blown out....but that would explain the steering wheel shaking at idle though....just never seen a riv mount that blown out b4.

So after reading you guys' tips and suggestions, I think i'm going to replace the whole s/c tensioner and wait on the mounts b/c they haven't shown a clear indicator that they are the issue. But i do plan on replacing them soon, just not now. Any suggestions on where I can get the whole tensioner at a fair price. It's looks like an easy DIY job from the write-up.

3.8 Riviera wrote:

So after reading you guys' tips and suggestions, I think i'm going to replace the whole s/c tensioner and wait on the mounts b/c they haven't shown a clear indicator that they are the issue. But i do plan on replacing them soon, just not now. Any suggestions on where I can get the whole tensioner at a fair price. It's looks like an easy DIY job from the write-up.

As for the tensioner, "let your fingers do the walking" and just call local auto parts stores to find it. I don't live in your area and so can't say who will have it at any price. IT is definitely not a rare part and you should have no trouble finding it.

Now, if you can wait a couple days I suggest http://www.rockauto.com to order over the internet, or http://www.monsterpartsonline.com (shopgmparts.com). Tensioner should be $155 to $165 from a GM dealer, unless they cut you a 'cash and carry' price break. Probably less than 1/2 that from rockauto. Somewhere in between from another store.

Closing remark: I'll give you a hint: if the tensioner was bad it would scrape all the time, not just sometimes. The changes in the scraping tells me your motor mounts have issues or the wrong pulley is on the tensioner -- you did not say if you ever measured pulley diameter. It's a close fit and the larger one would scrape sometimes. Just the same. knowing that your tensioner has not been replaced hints to me that you likely want to replace it anyway. So I could be full of it but I predict that either you will replace the tensioner and still have the scraping problem, or you will be unable to replace the tensioner because the arm of that motor mount will be in the way. And oh by the way be sure to get a torx bit for the tensioner pulley or getting that belt on/off without damage will not be possible.

Keep at it though.. once you get the car back up to a good level of maintenance it won't give you much trouble. High mileage stuff like the motor mounts and the tensioners are not in the maintenance schedule because most people don't keep their cars that long.

By the way - is your "check engine" light on?

I'm willing to keep this car b/c it's rare around here but it has a unique modern style that can't be touched. I'm planning on having a mechanic give a diagnosis this week. I looked at the transmission mounts today and they look fine. It's just a LOT of oil in that area. I don't know which gaskets are blown out, or truly what's going on down there. The pulleys have never been changed so i'm assuming they came with the car back in '04. I'm truly hoping these pins in the pulley have failed b/c it's an under $100 dollar job. But the mounts will be replaced soon. I looked at the accessory belt today and i noticed as if there is some unusual wear on the flat side. Maybe the engine is leaning and rubbing on something. I'll find out this week.

p.s. how well do clay bars work. i'm trying to remove harden tree sap off my the paint.

3.8 Riviera- wrote-" it's an under $100 dollar job"
lol! what part of the U.S. u livin in? ain't nothin "under a $100" if someone else is doin the work!!
Clay bars suck. an initial investment of a good buffing job, keep your car clean,and a clay bar application wont ever be necessary.

3.8 Riviera wrote:

I'm willing to keep this car b/c it's rare around here but it has a unique modern style that can't be touched. I'm planning on having a mechanic give a diagnosis this week. I looked at the transmission mounts today and they look fine. It's just a LOT of oil in that area. I don't know which gaskets are blown out, or truly what's going on down there. The pulleys have never been changed so i'm assuming they came with the car back in '04. I'm truly hoping these pins in the pulley have failed b/c it's an under $100 dollar job. But the mounts will be replaced soon. I looked at the accessory belt today and i noticed as if there is some unusual wear on the flat side. Maybe the engine is leaning and rubbing on something. I'll find out this week.

p.s. how well do clay bars work. i'm trying to remove harden tree sap off my the paint.

If the mounts are OK don't mess with them... a mount that is not OK has little cracks in the rubber...

On the Riv the flat sides of the belt get a good bit of wear from orlling over the idlers. What you are looking for is cracks in the rubber on either side, the belts are tough, if you have more than a few cracks per inch it's time to schedule belt replacement. when you replace belts then turn the pullies by hand and replace any that squeak or grind.

robotennis61 wrote:

keep your car clean,and a clay bar application wont ever be necessary.

False.

I keep my paint immaculate. I can wash, clay, and wax it, then drive around for the day and come home to particles in the paint. This is most noticeable on a white car and unless you keep the car off the road and in a garage you will eventually have to clay or buff the paint. Paint is too porous and there are too many things in the air to not have to clay at some point.

You can remove the same stuff that a clay bar does with light compound, but why? You are degrading the thickness of the clear coat each time you buff it. On the other hand clay bars leave micro scratches that must be removed with light compounds (though not usually noticeable unless its a black car).

Off topic, sorry.