opinions needed, potential timing chain system failure?

[Nekomimi]

Ok, so starlady's 92 SC2 has close to 90k miles and has a rattle that happens at low rpm(like shifting into reverse) and then goes away at normal idle. The sound is coming from the passenger side of the engine. It sounds like the tensioner rattle, but it's new and very tight. plus the slightly shorter accessory belt is installed.

From my own experience, after slowly hearing mine deteriate over months until it broke. I swear that its identcle. So I was hoping to get other opinions of what to check to make sure that it is, or it isn't a timing issue. I'm leaning towards it being worn out chain guides.

[Ionizen]

Light rattle only when in reverse. Mine did that (only with the A/C on). My Local independent suggested a new belt/pulley/tensioner. Fixed the problem right up. I would think if it were timing chain related it would start to rattle upon initial start up, not wait until only going in reverse.

[Highmile]

Remove the belt and try it again to rule out all belt and belt driven issues.

Also make sure the rattle isn't coming from another source like catcon, head shields, etc.

Highmile
'95 SL1 626k and counting

[OldNuc]

Originally Posted by Nekomimi

Ok, so starlady's 92 SC2 has close to 90k miles and has a rattle that happens at low rpm(like shifting into reverse) and then goes away at normal idle. The sound is coming from the passenger side of the engine. It sounds like the tensioner rattle, but it's new and very tight. plus the slightly shorter accessory belt is installed.

From my own experience, after slowly hearing mine deteriate over months until it broke. I swear that its identcle. So I was hoping to get other opinions of what to check to make sure that it is, or it isn't a timing issue. I'm leaning towards it being worn out chain guides.

If you get slack in the chain from guide wear you will hear a different sound from the timing case depending on the direction of the chain loading. To test this you lightly increase RPM to 11800-2200 by hand at the throttle body and then let go of the throttle shaft cam and allow it to snap shut. If there is chain slack you will hear it as the load direction changes. Do this with a cold engine and the belt off as other parts can make an almost identical sound. A good mechanics stethoscope is also a big help. That mileage is a bit low for having this type of failure but not incredible.

A small exhaust leak can mimic this noise as well and those leaks are found by pressurizing the exhaust and a bubble test. There are multiple gaskets in that system that can fail and a tube header that can crack.

[buffalo14052]

I agree with both of the above posters. I'd pull the serpentine belt off and run the vehicle with the belt removed (don't go too far). If it still makes the noise you've eliminated the alt, p.s. pump, belt tensioner and pulley, idler pulley and ac compressor. The idler pulleys like to go on these and do have a noise similar to a timing chain.

[OldNuc]

When a timing chain issue is easily diagnosed on a DOHC Saturn it is an immediate turn it off and fix it now issue. They are very difficult to properly diagnose in the very early stages of degradation as lifter rattle and other odd events will mask chain whip easily. With a 20+ year old car with only 90,000 miles on it the cause is most likely guide wear and not a significant cause of immediate failure. Guide wear can be checked to verify diagnosis for the cost of a cam cover gasket.

[Nekomimi]

Wow! You guys are the best, I'm going to make a checklist to work through. I agree, the miles are pretty low for this problem to occur. Its just so similar.

Ok, so any speculations as to what might cause early wear?

[Jonasan308]

I waited until nighttime, then i took a light, started the engine and looked down in the space to look at the tensioner pulleys. If you look at them, theres a bolt in the center and it should not be moving. Mine had one in the center that was moving whenever the throttle was applied, and was jumping around considerably, making a clatter that got worse as revs dropped and also would consistenly make the noise while the A/C was on.

[OldNuc]

Originally Posted by Nekomimi

Wow! You guys are the best, I'm going to make a checklist to work through. I agree, the miles are pretty low for this problem to occur. Its just so similar.

Ok, so any speculations as to what might cause early wear?

Age would be the primary item for guide wear as I doubt that the engine is run low on oil. I would first suspect the tensioner as every aftermarket tensioner I have ever found has a short service life.

[Nekomimi]

Originally Posted by Oc

Age would be the primary item for guide wear as I doubt that the engine is run low on oil. I would first suspect the tensioner as every aftermarket tensioner I have ever found has a short service life.

Right, this one is brand new and is supplying proper tension.

[StarLady]

Originally Posted by Nekomimi

. . . I agree, the miles are pretty low for this problem to occur.

The mileage is low but not *that* low. It's actually around 110,000 now (yeah, broken odometer).

Thanks, Nekomimi for starting this thread.
And yes, SaturnFans members ARE the best!

[OldNuc]

Originally Posted by Nekomimi

Right, this one is brand new and is supplying proper tension.

Brand new aftermarket means nothing, all of them can be making much noise as there is no damper in these at all, they will oscillate at some point as they are a flat spring working against a cam surface.

[nealt]

I had the same problem in September 2016. All the "new" aftermarket tensioners would rattle on my car. This happened when I put the car in reverse or had the AC on at idle. Even a brand new NAPA brand Gates tensioner had the same problem. I ended up going to a junkyard and pulling off an old OEM tensioner and using it.

...rattles NO MORE.

[Saturn Night]

Timing chain would rattle at any given rpm. It doesn't hurt to check the guides, with the age of the car. I doubt it is the timing chain. This is a Saturn 1.9L, not a 2.2L Scrap-O-Tech or anything offered over the last 30 years by Chrysler Corporation......

[OldNuc]

It is very difficult to find a DOHC timing set that is in such a degraded condition that it actually rattles at any RPM.

[Saturn Night]

Originally Posted by OldNuc

It is very difficult to find a DOHC timing set that is in such a degraded condition that it actually rattles at any RPM.

Only because the connecting rods usually go from the low oil events, first.

Honestly, as much as Starlady investigates EVERY squeak, rattle, noise in her car, I doubt she ever lets the oil get low or goes too many miles before changing the oil.

She has probably followed her mileage service intervals to the letter, and made sure to properly care for her SC2, the way every Saturn owner should have(because had they done so, they would still be driving a rust-free, dependable car, that gets between 30-40mpg)

I highly doubt it is her timing chain. I agree with your assessment on the replacement tensioner pulley, OldNuc.

I am finding out, as a now 6-month Saturn S-Series owner, that most aftermarket parts for these cars are barely above average quality, and OEM was just overall the best parts for these cars.

Normally, I am ok with not scouring salvage yards, for countless hours, to find a replacement part. I just head to NAPA/AZ/AAP/O'Reilly's, and get something off the shelf.

My Saturn is the exception. I go to the wrecking yards, FIRST, and if I can find it but I absolutely NEED it, then I get is from the big chain stores or an online supplier.

[OldNuc]

I have been making that point as long as I have been on here that most, if not all aftermarket parts are mediocre quality at best. Mechanical internal engine parts are the exception, if you choose wisely. If you buy parts from Asian sources you will find they have highly variable quality and what worked 3 years ago is now just overpriced junk. Items with a definite legal liability attached and purchased from identifiable sellers will be OK however. That would be brake and suspension parts.

The easily detectable sound from a bad DOHC timing chain is the sound you hear when the mechanical engine timing is either early or late. You can not read this on live data either.

[Nekomimi]

I actually found a good OEM tensioner today at the LKQ that we could try. Sorry for the confusion on my end, I didn't realize that it would still hit with low rpm.