Q: I have a 2017 VW Turbo Jetta. I always service the car at the dealer where I bought it. I am scheduled for my next service on May 15, when my estimated mileage will be 60,000. I am currently at just under 55,000 miles. Obviously, I won't reach 60,000 miles unless I drive cross-country twice in the coming week. So, my question is, do I take it in based on the date or the mileage?
A: Oil change intervals are disappearing in favor of mileage intervals and service reminder lights. For most other motorized devices such as airplanes, maintenance is based on hours of operation, so a car's mileage roughly correlates to time of operation. Many service facilities still give owners reminders based on time but check your manual's maintenance schedule. The reminder on your instrument panel will tell you when it is time to do an oil change.
Finding elusive oil
Q: I recently was gifted a 1979 Negrini moped. It has a 49cc, two-cycle engine. After some extensive cleaning it appears to be in good condition. The owner's manual calls for the gas oil mix to use 20 weight motor oil. (It also is used in the transmission). I have not been able to locate a source for straight 20 weight motor oil. I have concern about using any other type or weight of oil in the gas mix, because of plug fouling or engine seize. Can you offer a suggestion for source of 20 weight or a comparison chart of current two-cycle oil equivalents?
A: I turned to an expert chemist, Tom Wicks, who has created stuff and consulted for several well-known engine products companies. "The 1979 Negrini moped could probably easily run on old French fry vegetable oil," he joked. Tom said that two-cycle oil is fine for the engine and automatic transmission fluid would be best for the gearbox. Any two-stroke, air-cooled, chainsaw oil at a 20:1 ratio is fine. Ace hardware carries a synthetic oil that keeps things clean.
Battery sensor can mislead
Q: Your recent article regarding a Ford Escape battery not staying charged, and being repeatedly replaced, may have to do with the battery sensor, located on the negative terminal. It tends to corrode and not allow the vehicle to properly charge, even if the battery is new. My son's 2013 had the same problem. Ford diagnosed the sensor as bad, and the battery has been good since.
A: Many vehicles, not just Fords, have battery sensors to provide information to the body control module (BCM). The module uses the input for many systems as well as to determine the battery state of charge to activate the alternator and even to control the stop-start systems if the battery gets low. Dirty and corroded terminals are the most common problems. Look for the connector at the negative battery terminal, but some makes put it on the positive post and others even use one on both terminals.
Bob Weber is a writer, mechanic and ASE-certified Master Automobile Technician. His writing has appeared in automotive trade publications, Consumer Guide and Consumers Digest. Send automotive questions along with name and town to motormouth.tribune@gmail.com.
