Automania/Repair & Maintenance

Auto Questions And Answers For Week 45 Year 2001

by Bob Hagin

Q. I have an '00 VW Jetta with a 2.0-liter engine with 20,000 miles. It developed a noise at 17,000 miles that sounds like something is loose in the engine. In the morning the car makes a clicking noise between 2000 to 3000 RPM but I can't hear it on the Interstate. I took the car to the dealer and they said it had a piston slap and they'd have to keep it a few days. I dropped my car off and they gave me a loaner Jetta with the same engine. We immediately noticed that it didn't make the same noise. They kept my car for three days then told me that the noise could be because I used a so-called aftermarket oil filter. The service representative at VW said that VW oil filters are different from other brands. I have my car serviced every 3000 miles and check the oil level in the engine at least once a week. The car uses a bit of oil but VW told me it's normal. I added a quart of oil to my car every two months.

A. The noise called piston slap is caused by one or more pistons having too much clearance between their side skirts and the cylinder walls. In effect, the pistons become too small and wobble in the cylinder bores. It can be cause by an engine simply wearing out (not common any more), a piston seizing because of a lack of lubrication (it runs out of oil) or it's put together wrong. This is easy to check and usually it doesn't happen to all the pistons. But there could be other causes, none of which could be caused by a "wrong" oil filter. Find out what brand oil filter your shop uses and call its service reps and tell them your story. Check if your owner's guarantee says you should use only VW filters. Also find out if the "service representative" was a factory guy or an in-house mechanic. Try another VW dealer's shop, too.

Q. A few weeks ago my '97 Olds alternator went bad and took the battery with it. We had to get it towed to the dealer and the bill ran over $500. This has happened to me with other more vintage cars too. My question is this: If we can fly people to the moon, why can't we install warning lights or gauges to alert the driver to a battery that's not getting charged or an alternator that's going bad? In the old days, '50s and '60s, such gauges were standard and I always knew in advance if my battery was going bad or not being charged and I never got stranded on the highway with a battery problem.

A. Astronauts are trained to monitor a complex set of instruments at all times when they're in flight while motorists are not. Auto industry market researchers know that most vehicle buyers only look at the fuel gauge and don't know what it means if "idiot" lights come or ancillary gauges reflect a malfunction, so they cut costs by excluding them. Even temperature gauges are ignored until it's too late. I imagine that aftermarket gauges could be installed in late model cars but it might be hard to find a technician that would do the job and dashboards are so esoteric that it might be hard to find a place to mount them.

Q. It's time to rotate the tires on my '97 Acura 3.5 RL that I bought earlier this year. The owner's manual says to for non-directional tires and wheels to use a half-X rotation, i.e. front wheels move straight back to the rear and rear wheels cross over to the opposite front sides. changing the direction of rotation for two of the tires each time they're rotated. The markings on my tires are identical and nothing indicates a required direction of spin. The tires are not original equipment. I've seen pamphlets that suggest only a front-to-back rotation.

A. When you're in doubt, go with the factory recommendations on service. The main purpose for a rotation is so the tech can check suspension alignment, tire wear and even simple tire pressures, a neglected item.