Automania/Repair and Maintenance

AUTO QUESTIONS AND ANSWERS FOR WEEK 43

by Bob Hagin

Q. I recently went to a kit-car show and have been toying with the idea of starting one myself using a VW. I think I have enough skill and tools and it would be a good way to get my 15 year old son out of music and into something constructive. What kit would you recommend? T.T. Milton, WA

A. I hope son doesn't read this column. A fellow shop teacher felt the same way, bought a Cobra kit and had to finish it himself. His son never lifted a wrench on it. If you start a car yourself, be ready to spend a lot of time and money and make sure your garage is heated. At 15, the worst thing you can do is to try to try to force a boy out of one interest and into another. My youngest son was almost 30 when he got into cars but 15 years ago, all he wanted was to rock-and-roll.

Q. About a year and a half ago my son switched the motor oil in his 1992 Nissan Pathfinder from a standard petroleum-based oil to a synthetic brand. At the time, it had around 75,000 miles on it. He didn't prepare the engine in any way but simply drained out the old oil and installed the synthetic. He now tells me that the engine is burning about a quart of this expensive oil every 400 miles. Could the switch to synthetic oil have caused this problem? Would switching back to a petroleum-based oil cure it? R.H. Danville, CA

A. The adage "Don't change horses in the middle of the stream" can also apply to motor oil. Also applicable is "If it ain't broke, don't fix it." Most mechanics and lubrication engineers suggest that a synthetic oil should only be used when the engine is first broken in as new or after a rebuild. Some synthetics seem to clean out the carbon build-up and residue that may be sealing up piston rings, cylinder walls, aging seals of all kinds and gaskets. Some synthetics are more prone to do the cleanup act more than others so oil switchers are always taking the oil-mileage characteristics of their engines into their own hands when they switch. I'm not a great fan of synthetics since modern engines can go 200,000 miles or more by simply changing the conventional (and relatively inexpensive) oil and the oil filter every 3000 miles. Changing back to a petroleum-based oil will probably help your son's Nissan but it may take going to a straight 30 weight oil rather than a multi-grade and it may take some time and mileage to slow down the oil consumption.

Q. I drive a '94 Ford Taurus and take it to a quick-lube shop for basic oil changes. I keep the receipts and try to question the people doing the work about any concerns that I have. Sometimes I'm not sure that they are being completely honest with me. I found that the dealership charged me more than I expect on parts and labor on some work I had done some time ago. The quick-change shop is very thorough but when they bring various problems to my attention, I sometimes wonder if they are just making work for themselves. Do you have any suggestions on services that need to be done? Years ago, my father told me that if the automatic transmission is rust-colored, it needs changing. The mechanic that does my oil changes said that there is more to it than that and that the answer was too technical for me to understand. M.H. Virginia Beach, VA

A. I've found that if the oil and its filter is changed twice as often as the auto maker recommends, you can't go wrong. Modern automatic transmission fluid (ATF) is very long-lasting and efficient - but I recommend changing it and its filter every two years anyway. It gives the technician a chance to inspect the pan for ferrous and non-ferrous residue that can indicate trouble. ATF is cheap compared to transmissions. If a big job is recommended, get a second opinion from another shop if you're antsy.