Question - We've had a spate of flats lately. The latest was on our Ford Taurus. The puncture was right at the edge of the tread. We had it fixed at a gas station, and the attendant used only a plunger with a "rope" attached. He said it might not hold because it was so close to the edge. I am concerned about the safety of the tire. I checked some of the tire safety-related sites on the Web, and most indicated that both an inside and an outside patch were needed for a safe repair. What's your advice ? - Carl

TOM: An inside and an outside patch, Carl. Especially if the puncture is large or close to the side-wall.

RAY: The "outside patch" or "plug" is an easier fix. That's what you got. That can be done without taking the tire off of the rim. And in many cases, it's good enough.

TOM: But if you really want to do it right, you should also apply a patch inside, which goes inside the tire, right over the puncture. In addition to the adhesive, the internal patch is kept in place by outward force of the air pressure in the tire.

RAY: And if your mechanic still has any questions about whether this particular tire is going to be patchable, just forget about the patch and replace the tire. Your family's safety is worth $100, isn't it, Carl?

Question - My father-in-law keeps pushing me to purchase any turbo diesel-powered car. I drive 132 miles a day to work, and he keeps telling me about how much I could save.

The problem is, he's not advocating that I use diesel fuel! He fills his diesel truck up with home-heating oil, which ends up costing him around 60 cents a gallon. He claims there's very little difference between the two fuels. My question is: Has he gone over the edge? Can home-heating fuel hurt a diesel car ? - Kevin

TOM: Well, Kevin, your father-in-law hasn't gone "over the edge" in terms of sanity. But he has gone over the edge of legality! What he's doing is blatantly illegal. In fact, the FBI dogs are sniffing your envelope as we speak!

RAY: Home-heating oil and diesel fuel ARE essentially the same thing. There are some additives in diesel fuel that don't show up in heating oil, but it's basically the same primordial crud.

TOM: The difference in cost is mostly a result of the taxes. There are a variety of gasoline taxes imposed by federal and state governments that support things like road repair. And by using home-heating oil (which is exempt from these taxes) in his truck, he's breaking the law and, effectively, stealing from the rest of us who DO pay our taxes.

RAY: So if I were you, I wouldn't join in this scheme that your father-in-law is perpetrating, Kevin.

After all, if you get caught, the fines for tax evasion will more than wipe out anything you save on the road. And besides, what could be worse than spending 15 years in a small cell with an in-law?

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You can order the booklet by sending $3 and a self-addressed, stamped (55 cents) No. 10 envelope to Ruin No. 1, P.O. Box 6420, Riverton, NJ 08077-6420.