Q–I own a 1994 Chevrolet G20 van with a 350-cubic-inch-displacement engine and 64,000 miles on the odometer. I am ready to replace the serpentine belt for the 10th time since the van was new. Each one begins to squeal 1,000 or 2,000 miles after replacement. I (and my neighbors) live with the initial scraping sound, but eventually it turns into a semi-constant squeal. That’s when I replace it, usually after 5,000 or 6,000 miles.
The dealer replaced two of them under warranty, though belts are not covered. He agrees that this is, indeed, a problem, but can’t locate the cause. The tension on the idler pulley is up to spec, and the air conditioning compressor has been replaced. I applied a belt dressing at one point, which helped temporarily, but the mechanic blamed the squeal on the dressing. What else could possibly be the cause? M.H., Chicago
A–One of your pulleys is probably out of alignment, and if the problem began after the air conditioning compressor was replaced, it would be the prime suspect.
Using a spray bottle, mist the belt with water as the engine is running. If the noise decreases then comes back, perhaps even louder, there is misalignment. (If the noise increases when you spray the belt, it is slipping.) To double-check the misalignment, remove the belt, flip it over and reinstall it. If the noise goes away, or decreases, you have nailed the problem. You may have to shim one of the accessories (alternator, power steering pump, A/C compressor, etc.) or move the pulley if it is press-fit to the shaft. Gates Rubber Co. offers a belt with new elastomeric compounds that is more resistant to noise. Check with your local parts store.
Q–My 1996 Chevrolet Tahoe owner’s manual makes no mention of the top speed at which I can drive in four-wheel-drive or the speed I should not exceed when shifting between two- and four-wheel drive. Perhaps Chevy is relying on the operator’s common sense. There are times, when pulling three snowmobiles to Michigan’s Upper Peninsula, that I feel 60 m.p.h. is appropriate because there are only scattered slippery spots on the road. What is your recommendation? J.Z., Chicago
A–We are going to use the same kind of “wiggle words” carmakers use by saying that it is safe to shift into and out of four-wheel-drive at any legal speed. We interpret that to mean just about any speed since at least one state (Montana) does not post a speed limit on some highways.
As for the top speed at which you can drive in 4WD, we suspect that it is the same as the top speed on your speedometer unless there is a specific warning against doing so in your owner’s manual. You must be in quite a hurry to reach the U.P., eh?
Q–I own a 1995 Chevrolet Lumina. I detected a sliding noise coming from the front passenger seat when I applied the brakes in a hard stop. I believe the noise is coming from the air-bag sensing device bolted to the floor below the seat. To verify, I would like to disconnect the cable going to the sensor unit and temporarily take the unit out of the car. Will I cause the air bags to inflate by unplugging the unit? J.M., Chicago
A–If you hear something under the seat, you may have something under the seat such as a pop can or coins. There also could be a problem with the seat frame, upholstery or track. We have not heard of noisy sensors and would advise against fiddling with it. Take your car to a qualified technician because a goof with the air-bag system could be costly.
Q–I have a 1996 Chevrolet Beretta with 22,000 miles on it. At around 21,000 miles, the brakes started squealing, at first just when I braked, but soon even when I turned. I had the front brakes done at a cost of $260. Now, barely 1,000 miles later, the brakes are squealing again.
I brought the car back to the dealer and he blames it on being required to use metallic pads and says “the brakes will just squeal.” Is this normal? Am I unrealistic to think that 21,000 miles is extremely early for a brake job? I do a fair amount of city driving, but I change the oil every three months and do all recommended maintenance. K.R., Alsip
A–Because most of your driving is in the city, 21,000 miles on the front brakes is not bad. But you need not put up with the squealing. Since all sounds we hear are a result of something vibrating, there must be something loose; it is probably the brake pads. Take it back to the shop and ask them to get rid of the noise. If it were normal, the noise would have been there when you bought the car.
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Bob Weber is an ASE-certified Master Automobile Technician. Write to Motormouth, 17717 Silcott Springs Rd., Purcellville, Va. 20132. Send e-mail with name and hometown to motormth1@aol.com. Answers will be supplied only through the newspaper.
