Tensioner rattle is back -- even with new AC Delco tensioner and belt!

[2003MercMaraude]

I originally had the infamous belt tensioner rattle w/ an aftermarket plastic pulley POS tensioner and a 780 belt. I replaced with a real AC delco tensioner and the correct -778 belt. The rattle was gone for over a year. Now that I am starting to use the AC again, the extra load at idle of the AC, is making the tensioner rattle loudly again. I don't know how this is possible since I am using the expensive delco tensioner and belt and there are only about 15k miles on them.

I am going to replace the belt and see if that helps, but this is such a bad designed tensioner if that is the case, and it can't handle any belt wear.

The only other thing I can think of is using a shorter than stock belt (shorter than the 778 belt) to force the tensioner to not run out of travel

Man this is annoying

[OldNuc]

Do you have a metal or plastic idler pulley? They are slightly different diameters.

[2003MercMaraude]

The idler is the OEM metal one and it turns freely.

I put another used 778 belt of a different brand on last night and the rattle is gone so far.

It looks like the "780" belt some brands spec for these cars is 3/8" shorter than the stock "778" belt but I am using the "778" belt which is correct.

WIth a new ish belt and the AC delco tensioner, the tensioner is basically almost at max wind-up when the belt is at rest. If it wraps up too much further it hits the stop, which is what it seems like these things do when they make noise.

So I might have to try a longer belt than the "778" belt to try to get the tensioner more towards the middle of its range.

[OldNuc]

The effective belt length is longer with a worn belt. This is a game you play to get a tensioner and belt that will play together quietly.

[2003MercMaraude]

I know but 15,000 miles in one year should not yield a belt too stretched to tension. I am having the opposite problem, the tensioner is hitting the stop because the correct length, slightly used belt, is too short

I have owned a bunch of serpentine belted cars and I have never had something so finicky. the whole point of a tensioner is it's supposed to be less hassle than a manually tensioned belt.

[DavidJames]

Does anyone have a photo of the original (OEM) Saturn belt tensioner? There appear to be three holes for the original tensioner, two on the top and one and one on the bottom. The aftermarket belt tensioner that everyone is selling only uses two bolts, one on top and one on the bottom. It only has a one year warranty and is prone to failure in less than one year.

I bought one of these aftermarket belt tensioners from Autozone and it started rattling less than one year later, when I turned on the AC. During this period, my car sat parked most of the time. I put less than 6000 miles on the car since changing the belt and belt tensioner, less than half that with AC on.

The folks at Autozone told me to tighten up the bolts to see if that fixed the problem. SO I did, and it did not fix the problem. So I went in and got a replacement tensioner from them under warranty.

Now I needed an extra bolt since I rounded down the head on the top bolt trying to tighten it per their instructions. The manager at Autozone claimed they did not have one. So I went to Advanced Auto Parts. That is when I discovered Advanced sells the very same belt tensioner.

So I bought a set of bolts from Advanced, and put them in. It immediately stripped out the treads on the engine assembly. As it turns out the vibration from the tensioner fatigued the threads on the engine assembly for the top bolt causing the threads to soften. Also, more info, the place where the tensioner bolts on appears to be a separate part (a separate plate) that Saturn made from aluminum instead of cast iron.

Now my Saturn SL2 with just 125K miles is ready for the junk yard, because I cannot bolt down the belt tensioner. Their doesn't appear to be enough space on the top bolt to put in a tapper, to tap in new threads without taking the engine out. Replacing the assembly plate may not be much easier.

My car, which is in perfect condition otherwise, with a newly rebuilt trans and leather. Any help on the subject would be appreciated. IT appears all our Saturns are headed for the junk yard because "Cash for Clunkers" and planned obsolescence. This could be the stuff for a class action. Does anyone know a good lawyer?

AVOID using aftermarket belt tensioner or you could be facing the same problem or worse down the road. If anyone else has experienced this problem, please make a follow up post.

[SLCraig]

I'm thinking a valid option for people with this problem is to get the old tensioner design from a 95 or earlier... They are metal, and don't really appear to ever break. My friend installed one on his 98 (from a 94 or 95) and its been working great for some time now. I have a plastic aftermarket one and it makes noise also. (OEM belt)

I wish these cars had mechanical tensioners like my Nissan

[PlasticCarsRock]

Originally Posted by DavidJames

Does anyone have a photo of the original (OEM) Saturn belt tensioner? There appear to be three holes for the original tensioner, two on the top and one and one on the bottom. The aftermarket belt tensioner that everyone is selling only uses two bolts, one on top and one on the bottom. It only has a one year warranty and is prone to failure in less than one year.

I bought one of these aftermarket belt tensioners from Autozone and it started rattling less than one year later, when I turned on the AC. During this period, my car sat parked most of the time. I put less than 6000 miles on the car since changing the belt and belt tensioner, less than half that with AC on.

The folks at Autozone told me to tighten up the bolts to see if that fixed the problem. SO I did, and it did not fix the problem. So I went in and got a replacement tensioner from them under warranty.

Now I needed an extra bolt since I rounded down the head on the top bolt trying to tighten it per their instructions. The manager at Autozone claimed they did not have one. So I went to Advanced Auto Parts. That is when I discovered Advanced sells the very same belt tensioner.

So I bought a set of bolts from Advanced, and put them in. It immediately stripped out the treads on the engine assembly. As it turns out the vibration from the tensioner fatigued the threads on the engine assembly for the top bolt causing the threads to soften. Also, more info, the place where the tensioner bolts on appears to be a separate part (a separate plate) that Saturn made from aluminum instead of cast iron.

Now my Saturn SL2 with just 125K miles is ready for the junk yard, because I cannot bolt down the belt tensioner. Their doesn't appear to be enough space on the top bolt to put in a tapper, to tap in new threads without taking the engine out. Replacing the assembly plate may not be much easier.

My car, which is in perfect condition otherwise, with a newly rebuilt trans and leather. Any help on the subject would be appreciated. IT appears all our Saturns are headed for the junk yard because "Cash for Clunkers" and planned obsolescence. This could be the stuff for a class action. Does anyone know a good lawyer?

AVOID using aftermarket belt tensioner or you could be facing the same problem or worse down the road. If anyone else has experienced this problem, please make a follow up post.

That's why you should never take advice from auto store counter-people (at least without getting a second opinion). In this case, unless it was ridiculously loose (actually wobbling around), tightening it couldn't help.

The tensioner is in the timing chain cover, right? If you can't tap it in the car, I think you can take the cover out with the engine still in. It might be best to simply replace the entire cover (from a salvage yard).

Cash for clunkers? S-Series Saturns didn't even come close to qualifying for that (not that it wasn't a ridiculously stupid program).

[DavidJames]

Originally Posted by DavidJames

Now I needed an extra bolt since I rounded down the head on the top bolt trying to tighten it per their instructions. The manager at Autozone claimed they did not have one. So I went to Advanced Auto Parts. That is when I discovered Advanced sells the very same belt tensioner.

So I bought a set of bolts from Advanced, and put them in. It immediately stripped out the treads on the engine assembly. As it turns out the vibration from the tensioner fatigued the threads on the engine assembly for the top bolt causing the threads to soften. Also, more info, the place where the tensioner bolts on appears to be a separate part (a separate plate) that Saturn made from aluminum instead of cast iron.

NOTE: The aftermarket bolts could also be to blame for stripping the threads on the timing cover. The certified mechanic that Advanced Autoparts sent over said the Advanced bolt were made of a harder metal. He called it a one time bolt (i.e. only to be intended to be used once, not unscrewed and used again). The DORMAN aftermarket bolts Advance sells were 1/16 of an inch longer than the Saturn OEM bolts. They were also wider at the tip, because they do not have the self-tapping, slender nose. The aluminum came out stuck to my OEM bolt like a helical coil, after I screwed it in and unscrewed it.

1996 Green Saturn SL2
1989 Suzuki Sidekick 4WD Convertible

[mattelderca]

Stripped bolts in aluminum.
The original bolts corroded in, can cause the new bolts to be loose.
Retap next size up to fix. SAE taps and sizes can be used without the need for helicoils or the like.
Cheap aftermarket bolts can be undersized or of cheaper metal than originals.
Always reinstall the original bolts. (unless torque to yield)
Lube you nuts and bolts before removal.

[DavidJames]

Message edited by admin per poster request.

Same problem here with 96 Saturn SL2. The original belt tensioner on my vehicle lasted 120,000 miles. The replacement I got from Autozone under the trademark of Duralast worked fine for 5,000 miles with a new Dayco belt. Then the belt tensioner started rattling when the AC was ON and the car was stopped.

Replacing the after market part turned out to be a costly repair. It involved re-tapping the upper bolt hole, which had been fatigued by the rattling. I discovered that it was stripped out, when I installed the replacement.

Autozone’s manufacturer turned out to be Dayco. Here is the closing argument from Dayco’s letter, “improper installation of not getting the tensioner mounting bolts torqued sufficiently.”, caused the bolt hole to strip out, lol.

But seriously, what will it take to get them to stop, a boycott and/or a class action? This is too much.

Here are the facts and the fix.

Use the Gates replacement (model 38112) with the metal pulley. It is the best match for Saturn OEM belt tensioner, maybe even better. The Saturn belt tensioner included a plastic seal for the spring compartment that can break up and allow corrosive contaminates to enter the spring compartment. You can pick this item up for at O'Reily for $10 more than the only product available form Advanced, Autozone and Pep Boys, which is that cheap Dayco tensioner that damaged my car (see previous posts). You can also go to NAPA and pay them almost twice as much for the same part.

The Dayco part may be repackaged under someone else's brand and packaging. That is the way it is at Autozone. It can be identified by the 1-2 inch portion of the spring wrapped in plastic being exposed that is crimped around the spring enclosure. The Dayco product I purchased had a plastic pulley. If you have this product installed on your car, replace it with the Gates product. Get the money back on your warranty, if you were lucky enough to catch the problem in the first year. Tell them it rattles when you turn the AC on, while you have it stopped in drive.

FYI: Dayco makes good belts. Dayco’s Poly Rib Belt Item 5050780 is not part of the rattle problem. That is what I have installed on my vehicle. However, I should note that it did squeal a little one time, when I cranked up the car with the AC left on. I mentioned the Goodyear belt in earlier dialog, because I forgot that I got it first, then took it back because it cost more money and it had no warranty.

FYI: Tightening the upper bolt is not part of the problem. It just needs to be snug. There are no torque specs published for attaching the tensioner other than those published for the OEM bolt, and where else it is used on your engine block.

Since I could not get a mechanic to give me an estimate to drop the engine and tap new threads, I got creative, and JB Welded a M8x1.25 stud in place of the bolt. Keep in mind there is not much room to work, maybe 3 inches, and you need leave enough room to get the tensioner bracket over the stud. So check the assembly of your solution before applying the epoxy.

I used a stud 35mm long (tip-to-tip) that roughly matched the original bolt length, which was 38mm long (tip-to-tip). Note: A 40mm stud like those I got for my Suzuki's exhaust manifold could actually work better. That way you could use a regular bolt with a lock washer. I was forced to use a thin nut that included a washer, built on.

As for Advanced Auto Parts, their manager per the DM, refused to share the Certified Mechanics report, claiming a conflict of interest, which suggests just one thing, they do not have your interest at heart, as they do not want to share the results of their investigation, as they continue to sell the faulty part as their only solution.

Autozone response was an unsigned form letter which attempted to absolve them of any wrong doing by revealing their supplier for their product that was branded under their Duralast label. So in turn, I also got an unsigned form letter from Dayco, which had been copied several times as evidenced by number of page edges that appeared on the paper, indicating that there was nothing wrong with the failed tensioner Autozone sent back.

As for the ASE Certified Mechanic on my block, they said the problem was with Saturn's design. When Autozone requested an estimate, they wrote one to replace the timing cover. Anyone wonder why he doesn't get any work from me?

I am a software engineer, the kind of person who has a real head for numbers, who remembers the price for every item I put in the cart, and catches the grocer making mistakes to get my food for free. That is small potatoes. This is big stuff people. It stripped out the bolt hole on the engine block, by hammering on the bolt until it fatigued the metal in the block. Tell all your friends, not just Saturn owners. The problem exists on other vehicles, and with most suppliers. Make sure they get the right part for the job.

[madpogue]

Been a while since I did mine, but doesn't the tensioner bolt directly to the block, just aft of the timing cover?

[hotrod205]

Originally Posted by DavidJames

So I bought a set of bolts from Advanced, and put them in. It immediately stripped out the treads on the engine assembly.

I worked at Advance last year. Advance only sells replacement bolts for a few specific applications and NONE specifically for a tensioner bolt. They gave you the closest bolt they had, which of course was not an exact match.

No matter what they say, there are NO parts that are equal in every way to dealer parts, and these stores do NOT have exact specs on specific bolts and usually not even a good selection of sizes. If you need a bolt go to the dealer or junkyard, especially on anything bolting to the engine.

I had a guy come in wanting a harmonic balancer bolt for a 1988 Pontiac Lemans, the one made in Korea. He just couldn't understand why we couldn't pull up the exact size in the computer, and wanted me to give him one "close, because he HAD to get home". I refused, because he didn't have another one to even compare to and there was no way I could possibly guess the size, length, and thread size of what it would be. He left mad, but I wasn't going to sell him something I knew was wrong.

[hotrod205]

Originally Posted by DavidJames

If you are interested in a class action, please email DavidJames@Netslinger.com. Put "Saturn Belt Tensioner Rattle" in subject line.

I think that's a bit much, even if they gave you a wrong part you should have compared it before installing and they can't be responsible for someone messing up a repair they weren't qualified to make. There is a reason there are schools and ASE certs for these type of things...

[Dr. Sprock]

drilling a steel bolt out of an aluminum housing can be a pain.

don't even mention stainless or i will puke.

what you do if you have room is,

1) file the burr off the broken bolt,

2) center punch the bolt, this will be a small ping, but it helps,

3) use a 1/8 inch drill and try to keep it centered, use tape on bit for depth,

4) after the pilot hole is done, chase the rest out with a 3/16 inch bit

5) re tap for bigger threads if possible, or just chase old threads if you did not mess them up,

[DavidJames]

The tensioner is in the timing chain cover? NO, you are wrong. I went to a local junk yard to get a timing cover. When they pulled it, I discovered that the tensioner connects directly to the ENGINE BLOCK. It sits next to the timing chain cover in its own cubby hole. They gave me the original tensioner bolts for my trouble.

FYI: This makes the damage considerably more expensive. A used timing cover is $50, a used engine block is more than $500. The time involved to replace the timing cover is nominal, when compared to the time required to replace the engine, the engine block, or drop the engine from the car to tap new threads. All the mechanics I talk to all want T&M. They are reluctant to give written estimates on this job, or return my calls.

As for wobbling around: After a few thousand miles use, the plastic aftermarket tensioner will start vibrating and rattle, when you turn on the A/C. You can actually see it vibrating when the A/C is on at engine idle. That is how I, and I imagine many others, have been able to locate the source of the problem.

Wish I had a video of that showing before and after turning on A/C. The vibration created by the aftermarket tensioner fatigues the upper bolt hole that holds the tensioner to the engine block making for a real nasty repair bill, when you get around to replacing the tensioner to fix the rattling. If you leave it alone, it make continue working for a while, but you are just putting off the inevitable ride to the junk yard.

Avoid the tensioner with the plastic wheel that is sold by every auto parts store I checked except one, Orielly, which sells only the more expensive one that resembles the GM OEM part.

[DavidJames]

Originally Posted by hotrod205

I think that's a bit much, even if they gave you a wrong part you should have compared it before installing and they can't be responsible for someone messing up a repair they weren't qualified to make. There is a reason there are schools and ASE certs for these type of things...

Wrong part? Kiss my patootie. It is the cheap part that all the auto parts stores except for one sell for your Saturn. The problem is with the part not the installation. Mechanics are bolting these cheap pieces of plastic crap on your Saturns right and left without giving it a second thought.

FYI: The ASE schools are there to make off money training. Advanced sent over an ASE Certified Mechanic to checkout the problem. I have echoed his assessment. The vibration caused by the belt tensioner fatigued the bolt hole on the engine block.

[DavidJames]

Originally Posted by hotrod205

I worked at Advance last year. Advance only sells replacement bolts for a few specific applications and NONE specifically for a tensioner bolt. They gave you the closest bolt they had, which of course was not an exact match.

No matter what they say, there are NO parts that are equal in every way to dealer parts, and these stores do NOT have exact specs on specific bolts and usually not even a good selection of sizes. If you need a bolt go to the dealer or junkyard, especially on anything bolting to the engine.

I had a guy come in wanting a harmonic balancer bolt for a 1988 Pontiac Lemans, the one made in Korea. He just couldn't understand why we couldn't pull up the exact size in the computer, and wanted me to give him one "close, because he HAD to get home". I refused, because he didn't have another one to even compare to and there was no way I could possibly guess the size, length, and thread size of what it would be. He left mad, but I wasn't going to sell him something I knew was wrong.

The bolts were not the problem. I tightened the after market bolts I got from Advanced into the block at the junk yard. The bolt holes in the block were plenty deep enough to crush the flanges on the tensioner, and the threads were compatible. The bolts were just a higher tensile strength than the originals, and not the cause of the problem.

What should have tipped me off to the problem? The aftermarket belt tensioner did not come with your typical aftermarket lifetime warranty. It only had a one year warranty, and it failed in 6 months.

[DavidJames]

Here are the facts and the fix.

Use the Gates replacement (model 38112) with the metal pulley. It is the best match for Saturn OEM belt tensioner, maybe even better. The Saturn belt tensioner included a plastic seal for the spring compartment that can break up and allow corrosive contaminates to enter the spring compartment. You can pick this item up for at O'Reily for $10 more than the only product available form Advanced, Autozone and Pep Boys, which is that cheap Dayco tensioner that damaged my car (see previous posts). You can also go to NAPA and pay them almost twice as much for the same part.

The Dayco part may be repackaged under someone else's brand and packaging. That is the way it is at Autozone. It can be identified by the 1-2 inch portion of the spring wrapped in plastic being exposed that is crimped around the spring enclosure. The Dayco product I purchased had a plastic pulley. If you have this product installed on your car, replace it with the Gates product. Get the money back on your warranty, if you were lucky enough to catch the problem in the first year. Tell them it rattles when you turn the AC on, while you have it stopped in drive.

FYI: The Dayco makes good belts. Their Poly Rib Belt Item 5050780 is not part of the problem. That is what I have installed on my vehicle. I mentioned the Goodyear belt earlier, because I forgot that I got it first, then took it back because it cost more money and it had no warranty.

FYI: Tightening the upper bolt is not part of the problem. It just needs to be snug. There are no torque specs published for attaching the tensioner other than those published for the OEM bolt, and where else it is used on your engine block.

Since I could not get a mechanic to give me an estimate to drop the engine and tap new threads, I got creative, and JB Welded a M8x1.25 stud in place of the bolt. Keep in mind there is not much room to work, maybe 3 inches, and you need leave enough room to get the tensioner bracket over the stud. So check the assembly of your solution before applying the epoxy.

I used a stud 35mm long (tip-to-tip) that roughly matched the original bolt length, which was 38mm long (tip-to-tip). Note: A 40mm stud like those I got for my Suzuki's exhaust manifold could actually work better. That way you could use a regular bolt with a lock washer. I was forced to use a thin nut that included a washer, built on.

As for Advanced Auto Parts, their manager per the DM, refused to share the Certified Mechanics report, claiming a conflict of interest, which suggests just one thing, they do not have your interest at heart, as they do not want to share the results of their investigation, as they continue to sell the faulty part as their only solution.

Autozone response was an unsigned form letter which attempted to absolve them of any wrong doing by revealing their supplier for their product that was branded under their Duralast label. So in turn, I also got an unsigned form letter from Dayco, which had been copied several times as evidenced by number of page edges that appeared on the paper, indicating that there was nothing wrong with the failed tensioner Autozone sent back.

As for the ASE Certified Mechanic on my block, they said the problem was with Saturn's design. When Autozone requested an estimate, they wrote one to replace the timing cover. Anyone wonder why he doesn't get any work from me?

I am a software engineer, the kind of person who has a real head for numbers, who remembers the price for every item I put in the cart, and catches the grocer making mistakes to get my food for free. That is small potatoes. This is big stuff people. It stripped out the bolt hole on the engine block, by hammering on the bolt until it fatigued the metal in the block. Tell all your friends, not just Saturn owners. The problem exists on other vehicles, and with most suppliers. Make sure they get the right part for the job.