Q. R.R. in Des Plaines asked why there are tachometers in cars (Cars, April 25). I was driving down the interstate (in Oregon) at highway speeds when I noticed my tachometer jump up in revolutions. It looked dry (it had been cold) but a light mist was beginning to fall, so I suspected I had hit a slippery patch and the wheel spin caused my tach to jump, and I coasted down to around 40 m.p.h.
I re-applied the gas, and immediately I was on black ice. Fortunately, I was on a flat, straight stretch, and I rolled safely to the apron. I attempted to step out of the car and found a bumpy glazed surface about a quarter-inch thick that was nearly impossible to stand on. I could nudge my car and make it slide. I inched my way along for an hour until a full-fledged rain began to melt the ice.
I was very glad I was given a heads-up by my tach.
J.C., Downers Grove
A. Not only was your engine revving, we bet your heart rate was up there, too. Thanks for sharing another good reason for a tachometer.
Q. I own a 1994 Mercury Grand Marquis with a 4.6-liter V-8 engine with 91,000 miles. It is used around town, but it does get driven on the expressway. Last spring/summer when the car had around 75,000 miles on it, I began to experience spark detonation (pinging) with 87-octane gas. I switched to 89 octane, which seem to help. I hadn’t experienced this before.
I took the car to an independent mechanic who cleaned the carbon build-up in the intake manifold. This helped for a while but I am having the same problem again. My mechanic also told me that carbon build-up like this was common with this engine, and I have read this. We are considering buying a 2002 Ford Explorer with the 4.6-liter V-8 engine. Do you know whether Ford has made any improvements to this engine to help prevent the excessive carbon build-up and pinging problems?
B.S., Schaumburg
A. The problem lies less with the engine than with the way you use your vehicles. City driving leads to carbon buildup in the combustion chambers–the tops of the pistons and the cylinder heads–which, in effect, increases the compression ratio. High-compression engines tend to ping, and most call for premium gas to prevent that. Cleaning the intake manifold does little to clean the combustion chambers.
Q. Is there a real difference between a synthetic oil filter and an original equipment paper filter? Recently an auto-parts store employee told me that because synthetic oil lasts longer than conventional oil, paper filters do not hold up as well.
He says over a few months the paper filter begins to disassemble inside, clogging the main passageway and diverting oil around the filter instead of through it. I have a hunch it’s baloney.
F.J., Westchester
A. Poppycock (or baloney). All major-brand filters are compatible with synthetic oils, and none disintegrate in service.
We have seen counterfeit filters cause problems, but the ones we saw were made of old soup and vegetable cans stuffed with shredded rags. They came in plain white boxes or counterfeit branded boxes.
The government cracked down on these a long time ago.
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Bob Weber is an ASE-certified Master Automobile Technicia. Write to Motormouth, 17717 Silcott Springs Rd., Purcellville, Va., 20132. Send e-mail, including name and town, to MMTribune@netscape.net. Answers will be supplied only through the newspaper. Bob Weber
