When was that lube job? Look in your log

``A little automotive bookkeeping can go a long way toward preventing car trouble,'' according to Dave Bowman of Allied Automotive, a major supplier to the auto industry. The car-care expert is talking about record-keeping. Boring? Not if you tote up the money you can save by following the advice of the experts in automobile preservation. With the average new car these days costing more than $12,000, the time spent with a notebook and pencil will pay off handsomely.

First, says Mr. Bowman, your automotive mileage book should be laid out in vertical columns, leaving room to jot down the date and mileage of each service job, as well as what you have done. Besides such major repairs as a transmission overhaul or brake job, keep an eye on the nitty-gritty operations as well.

Bowman suggests you keep a record of oil-and-filter changes and each time you add fuel. A sudden drop in miles per gallon can be a tip-off that something is wrong.

More than a watchdog on the operation of the engine and other components, a mileage record helps to keep you from missing vital but routine servicing.

``Time has a way of sneaking up on us,'' observes Bowman, and ``unless we've written it down, we're likely to believe the lube job of six months ago was done much more recently.'' It also can work the other way, he notes. ``Some people service their cars too often, thinking they've driven more miles than they have.''