Answers to questions motorists should ask

Believing that ''too many motorists don't know enough about their car,'' auto racer Lyn St. James has written a soft-cover auto-manual-sized book, ''Lyn St. James's Car Owner's Manual for Women'' (Tilden Press: $5.95), which aims to take some of the mystery out of buying, owning, and maintaining a car.

The idea behind it is not to replace the car manual in the glove box, but to supplement it.

Just another how-to book for motorists?

Maybe. But it's a good one if you want a concise, yet useful guide to an automobile. It's not a technical tome, which wouldn't be of use to the average motorist, anyway.

Specifically, as the title says, the book is directed to the woman driver, although Ms. St. James asserts it wasn't her idea to single out women.

''The publisher insisted on the title,'' she adds, believing that women are making more car-buying decisions today than ever before in history.

Of the $75 billion spent each year on new cars, almost half of it is spent by women, according to researchers at the Ford Motor Company.

''Women often lack technical knowledge and confidence when dealing with the 'experts' like dealers and mechanics,'' the author asserts. She could have gone on to say that men very often fit this description as well.

She urges any motorist to ''ask questions.''

Cars today are getting increasingly complex, and it no longer is a simple exercise for a motorist to tinker with the engine to make it run better.

It takes costly, computer-controlled equipment, which many smaller repair shops don't even have.

''It'll take years for the computer age to become efficient in the auto industry,'' the author says. This is hardly good news to the motorist. ''Unfortunately, the public is at the mercy of this learning process,'' she asserts.

Ever the racer, Ms. St. James says that ''every motorist should have skid-pad training,'' believing that if a driver knows how a car will behave under marginal road conditions, he or she will be in a better position to react behind the wheel.

The 160-page book, including index, gives tips on how, when, and where to buy a car, the 10 major systems of an automobile, how to recognize the symptoms of future car trouble, what to do if your car breaks down on the road, how to drive like a pro, plus other useful information. It's written in simple language and should be no puzzle to understand.

A music major and one-time piano teacher, Lyn St. James has been ''driving fast'' ever since she entered her first race on a dare at age 17.

Since then she has been racing cars from Daytona, Fla., to Sears Point, Calif., running an auto-parts business in Florida, and conducting car clinics for women from coast to coast.

''My mother taught me how to drive in a big boat of a car, a Pontiac Bonneville, with automatic transmission,'' she admits, ''telling me that the gas pedal will get me out of more trouble than the brake.''

While she would never think of racing a car without a safety harness, she's only been a belt-wearer in her road car for two years. Now she won't start the engine without buckling up.

For those who may never climb into the seat of a racing car and don't know a condenser from a crankshaft, this book is a useful guide.