Dear Tom and Ray:

My daughter in college has a 1986 Volkswagen Golf with about 50,000 miles. So far this year, we have replaced the heater core, both fuel pumps, a CV joint, the radio (partly her fault), the horn, the windshield-wiper motor and the whole exhaust system. What will be next? So far, the car and tuition are running neck and neck! - BobRAY: Well, Bob, that sounds about right to us. There's a formula we use to determine the maintenance costs for a car driven by a child at college.

TOM: The equation is M equals C - ADP - (ADB x 1.5) + (GPA x 2) divided by SAT + R/S + NFBHT.

RAY: So, to figure out what the maintenance costs should be, take the cost of the car minus the Amount Daddy Paid (ADP) minus the Amount Daddy Borrowed (ADB) times 1.5. Add in the kid's Grade Point Average (GPA) times 2, divided by her SAT scores. Then add the average number of Relationships she has per Semester (R/S) and the all-important Number of Friends she Brings Home for Thanksgiving (NFBHT).

TOM: So according to this formula, the next repair ought to cost you $217.59, and it'll probably be brakes.

RAY: Actually, Bob, just try to think of this as part of a good, liberal-arts education. Aside from learning philosophy, history and anthropology, your daughter's going to graduate with a great introduction to the fascinating world of parts and labor.

Dear Tom and Ray:

This past year I bought my wife a new Toyota Corolla four-door sedan. A short time ago, late at night, my wife had a rear flat tire. Since she was unable to change the tire herself and could not find anyone to help her, she drove the car with the flat three miles to our home. The next morning, I took the flat tire to a repair shop and had the nail hole repaired. I'm now using this tire as a spare. Would it be safe to drive the car with this tire on it? Would it be OK for everyday driving? Will I need to buy her another tire? - Herb

TOM: First of all, Herb, we want to commend your wife for doing absolutely the right thing. If you're not in a place where it's safe to change a tire, the best thing to do is to keep driving until you get someplace that is safe (like a gas station or your driveway). You may ruin a tire, or even a wheel, but that's a lot better than having your butt Simonized by a speeding semi while trying to loosen your lug nuts in the breakdown lane.

RAY: And the tire she drove home on probably IS ruined. Damage was certainly done to the sidewall, so it really isn't safe for everyday use.

TOM: In fact, it's probably not good to use it as a spare, either. A tire that's been damaged is unreliable. And you don't want your spare to be flat some day when you really need it.RAY: So your wife was a genius for having the presence of mind to put her own safety and welfare ahead of her tire's. And you should recognize that genius and buy a brand new tire. If you're a cheapskate like my brother, and can't stand to throw anything away, then turn the old tire into a swing for the kids or a garden planter. That's all it's really good for at this point.

Got a question about cars? Write to Click and Clack Talk Cars c/o King Features Syndicate, 235 East 45th Street, New York, NY 10017.