What could cause a grinding sound in a '99 saturn?

August 21, 2007 9:56 AM

What could cause a loud grinding sound in a '99 saturn?

I bought a used saturn a couple of years ago and its always made a grinding sound when accelerating. Its pretty loud and more than a few people have commented on it. I've put almost 20k miles on with this sound. It currently has 83k. I swear I've let a mechanic drive it for unrelated reasons once and he didnt even mention it (I might be confusing this with a different car).

Its a loud grinding noise coming from the right hand side of the car clearly from the engine compartment. It can be intermittent. I usually hear it in first and second gear, but also have heard it in third gear. If I let off on the accelerator it tends to go away or it just grinds much more quietly and intermittently.

I'm worried its the transmission, but I dont have any slippage or any other issues. I've recently replaced the transmission fluid as dictated by the maintenance schedule and havent noticed any difference.

I'll probably take it to a mechanic soon, but would like to be a little informed before going through the repair process. That is if it even needs repairs. Could it be something like a CV joint? Or the engine? Maybe this car is just loud? Its the sc1 with the wimpy 100hp engine.

posted by the ghost of Ken Lay to travel & transportation (8 comments total)

I doubt it's the transmission if it's still running fine and not slipping. Sounds more like an exhaust leak or a loose exhaust hanger.
posted by sanka at 10:18 AM on August 21, 2007

It could be any number of things, but grinding noises should always be investigated, and corrected. First thing to note is whether the noise is directly related to vehicle speed, or perhaps engine speed. If the frequency or amplitude of the sound changes only with vehicle speed, and is never present when the car is not moving, even if the engine is running, it's unlikely that the problem is with the engine. OTOH, if the noise can be made to change, with the car in park or neutral, just by revving the engine, you'd tend to look for engine related problems.

Common sources for rubbing or grinding noises are often related to brakes and suspension parts. A brake disc that is out of true by only a few thousandths of an inch, combined with a stuck caliper, can make a rhythmic noise that is vehicle speed related, that can sound very much like grinding. As can a tire rubbing against a bent control arm, or MacPherson strut coil spring. You can look carefully at your tires, especially the inside edges, to see if they evidence any wear, or if you see shiny spots on suspension parts under your car. You can also hear noises coming from air dams under the car which have been bent and are rubbing moving parts, or pieces of road trash which have been picked up in areas where they rub the vehicle.

Saturns are often a little misleading with regards to sounds and noises, because of their plastic body panels. But because they are fairly noisy cars, if you can easily hear this kind of noise regularly, you should certianly have the car checked for its source.
posted by paulsc at 10:24 AM on August 21, 2007

My bro's saturn "grinded" and howled like a banshee when the front wheel bearing was on its way out. (and he drove it like that for quite some time)
posted by davey_darling at 10:31 AM on August 21, 2007

Sounds like brake pads. But again, it could be ANYTHING.
posted by SirStan at 10:56 AM on August 21, 2007

Could be wheel bearings.
I would also suggest either the water pump or alternator, but both of those would've surely given-up by now.

Thing is, different sounds would be called "grinding" by different people. Is it a constant, low-pitched "box-full-of-marbles" sound? Similar to what a diesel semi sounds like at idle?
Or is it more of a higher-pitched metallic "zing-zing-zing"?
How about the sound of rubbing two metal pie pans together?

All of those could be called "grinding" by different observers...and each one would point to different problems.

And is the sound only heard while the car is in motion?
posted by Thorzdad at 12:25 PM on August 21, 2007

It might be an engine mount. I suggest this because my '95 Saturn is making similar noises and the top engine mount is in rough shape.
posted by donpardo at 12:49 PM on August 21, 2007

Some of the earlier suggestions are pretty good, but I just wanted to toss out that my mother's '94 Saturn dropped 5 quarts of oil over the course of a week and the motor just about burned up. Check your oil levels before you drive it again, just to be sure.

Is it louder turning tightly in one direction or the other? Forward or back? Wheel bearings are a possibility, as are CV joints.
posted by Pantengliopoli at 6:01 PM on August 21, 2007

20K miles on a bad wheel bearing would probably result in your steering wheel starting to shimmy back and forth. Nevertheless, check it out, as having a wheel fall off at speed is no picnic.
posted by BrotherCaine at 2:35 AM on August 22, 2007