ē Q. OK, this is going to be a bit of a long story ó sorry. As a college graduation present, my father got me a used 2004 Mercury Sable with 189,938 miles on it. When he gave it to me, he said it had only a small oil leak, but that leak turned out to be coming from the oil pan, and itís more than a small leak. I have to fill it every three to four weeks, which is getting expensive. So I took it to a friend, who is also a mechanic, and he discovered that my oil pan is welded in place, not screwed on, like it should be. So we are at a loss as to how to remove it and replace it without things getting really expensive. My friend thinks we should drop the engine and try it that way. What do you think we should do? ē

RAY: Iíd say fill it with oil every three to four weeks and start applying for sales jobs, because they sometimes come with company cars.

TOM: Youíre in a lousy situation here. Your oil pan is leaking, most likely because the gasket failed. Normally, thatís a pain in the neck, but not a horrible repair. But Iím guessing that at some point in this carís recent past, someone broke off the bolts that attach the oil pan to the engine block.

RAY: That would explain why they welded it back in place. The proper solution would have been to drill out the broken bolts and tap new holes, and use slightly bigger bolts to reattach the pan. But thatís a big and treacherous job, so they took the easy way out.

TOM: Your friend is suggesting that you do that job now, because it requires pulling out the engine.

RAY: But before you go to that length for a car with close to 200,000 miles on it, try a simpler solution. Start by thoroughly cleaning the area where the oil pan meets the engine block. Use a good solvent, like Brake Kleen. You can reach most of the oil pan from underneath the car with minimal removal of nearby parts.

TOM: Once itís been really well-cleaned, remove any rubber gasket material thatís hanging out, and then lay a bead of silicone caulk on the seam. Thereís a type of silicone caulk thatís impervious to oil, which you can get at parts stores, and thatís the stuff you want.

RAY: I would start by putting a thin layer of the caulk where the pan meets the block, and let it dry overnight. Then apply another layer the next day. Even if it doesnít completely stop the oil leak, it may slow it down.

TOM: And thatíll give you time to shop around for some really cheap cases of oil. Good luck.

ē Q. I just spoke to two different tire shops and got opposite answers to the same question. The right-side tire on my pickup is wearing quicker than the left. I have radial tires. I assumed it was normal, due to the way the differential works. One tire shop told me that I should be rotating in a cross pattern, while the other tire shop said that I should be rotating only front to rear. I was always told that reversing the tire rotation caused tire separation. Which answer is correct? ē

TOM: Well, neither shop gave you the advice you really needed. They should have told you that you need a wheel alignment.

RAY: Right. A right-side tire shouldnít be wearing any differently from the one on the left side. So if it is, somethingís mechanically wrong, and rather than rotate your tires and chew up another (now good) one, you should get that problem diagnosed and addressed first.

TOM: Depending on whether itís the front or rear right tire and what kind of suspension you have, a single tire can go out of alignment because the frame got bent in an accident, or because one or more of the suspension parts got bent or simply wore out. So the first thing you need is a good, old-fashioned four-wheel alignment ó along with whatever repairs are necessary to get the wheels to actually align.

RAY: Then, once your truck is properly aligned, you can absolutely cross the tires. You can cross all of them in an ďXĒ pattern, or you can cross just the two you move to the front. Or cross just the two that you move to the rear. If you have a full-size spare, you can add that into the rotation, cross three of them, put the spare on the right rear and toss the leftover tire in the trunk. Your options are limited only by your talent for origami and your ability to count.

TOM: There are a few exceptions. You can cross the tires only if you have the same size tires on all four wheels. If you have a muscle car, for instance, in which your rear wheels and tires are larger than your fronts, obviously, you can rotate only from side to side.

RAY: And if you have directional tires (some high-performance tires have treads that are designed to go only in one direction), you can rotate only front to back on the same side.

TOM: But for most people, tires can and should be crossed when theyíre rotated to even out the wear patterns and the pace at which they wear out.

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