Archive for Thursday, October 7, 1999


October 7, 1999


Dear Tom and Ray:

Would it be crazy to put a rebuilt engine in a 12-year-old car? I use my old Mazda wagon as a dogmobile for my dog-walking business. I've been looking at new cars, but I don't think I could stand it if the dogs scratched up the inside of my new car like they've done to this old one. Will a rebuilt engine give my Mazda a new lease on life? -- Sally

RAY: Absolutely. You're the perfect candidate for a rebuilt engine, Sally. In fact, the American Association of Engine Rebuilders will probably want you to star in their next TV commercial.

TOM: Here's your situation, Sally: You have a car which -- aside from a worn-out engine -- serves you perfectly well. So why spend a ton of money on a new, or newer, car that you don't even really want? Just throw an engine in it.

RAY: The one thing that you absolutely have to do, though, is have the rest of the old Mazda thoroughly checked out before you put the engine in. Have a mechanic you trust go over the old beast from headlight to tailpipe -- as if you were going to buy it as a used car. Find out everything that's wrong with it and factor that into your calculations.

TOM: So, for instance, if it needs new shocks, that's no big deal. You put in an engine and shocks, and you're happily toting the doggies around again.

RAY: But if you find out that you also need a new transmission and your frame is rusted, then you might want to reconsider.

TOM: I've got it. If it's not worth putting an engine in it, she could just rig up a harness and let the dogs pull HER. How many Pekingese does it take to pull a Mazda?

RAY: I'll have to look it up. But if the car checks out reasonably well, then by all means, toss in a new engine and keep driving, Sally.

Dear Tom and Ray:

I have a 1987 Olds Cutlass Ciera in very good condition with 67,000 miles. The brakes stop the car promptly, smoothly and without pulsation. The pads have been replaced once, and the rotors have never been machined. When I took it to a brake and muffler shop, they showed me that one side of my rotors was rusting. To me, it looked like little sand holes. I suggested machining that side, but the mechanic told me both sides would have to be machined, and that would make the rotors too thin to use. He wouldn't replace the pads unless I replaced the rotors. Can't I just have just one side machined? -- Abe

TOM: That's a good question, Abe, but the answer is no, you really can't machine just one side.

RAY: Theoretically you could. But in reality, the lathes are set up so that the rotors get pressed by blades from both sides simultaneously. If you apply pressure to only one side, the rotor will "give" whenever there's a bump or defect, and you won't really smooth out the surface, which is the whole point of machining. In other words, you'll get a lousy job.

TOM: How does he know? He's done LOTS of lousy jobs on rotors!

RAY: At 67,000 miles, I suspect your mechanic is right. The rotors probably are worn down to the point where machining them correctly would take them below specification (make them too thin).

TOM: Moreover, if only one side of the rotor is rusted, I'd be concerned that a caliper slide is stuck. Because when a caliper is working properly, the pads should be applying pressure to, and scraping rust off of, both sides simultaneously.

RAY: So this is not the time or place to be a cheapskate, Abe. You really want the calipers working properly and the pads and rotors in perfect, point-to-point contact so you get optimal braking. After all, those doughnut shops can come up on you awfully fast!

Dear Tom and Ray:

Our 1988 Pontiac LeMans is a piece of junk, but there's no way we can trade right now. The problem is condensation in the distributor. Almost every day I have to take it off and wipe it out to get the car to start; then it starts for the rest of the day. I've tried the spray, but that doesn't work. George, an 80-year-old ex-mechanic, says to put a plastic bag over it, but common sense tells me it would collect even more moisture, not to mention melt all over the engine. Someone else said to drill a hole in the cap. What do you suggest? -- Clyde

TOM: I'd check the supermarket, Clyde. I saw an ad that says Hefty has Sandwich Bags, Freezer Bags and now, "New, Distributor Cap Bags"!

RAY: Actually, the guy who said to drill a hole is closer to being correct than George is with his bag theory. I'll tell you a little story. We had a customer some years ago who drove an old Dodge van. And every three months, he'd come in because the van was running terribly.

TOM: And we'd take off the distributor cap and, sure enough, there would be so much moisture in there that mushrooms were sprouting on the inside of the cap.

RAY: So we got fed up one day and put on a new cap and sealed it with a whole tube of waterproof silicon sealant. We put so much goop on there that, when we were done, not a molecule of water could have possibly gotten inside. And we patted each other on the back and sent this guy on his way, confident we would never see him again.

TOM: Well, three months later he was back, and the problem was exactly the same. It turned out that the moisture wasn't coming from outside the distributor, but from inside. The distributor shaft was worn out, and moisture was coming right up that shaft from the engine. So, in effect, we made things worse by sealing all that moisture in!

RAY: And what almost all manufacturers have done since then is come out with vented distributor caps. The vent looks like a little smokestack with a cover on the top -- kind of like a chimney cap on a house. It's designed so that moisture can get out, but can't easily get in. And that's what you need, Clyde.

TOM: You should go to your local auto parts store and see if someone makes a vented distributor cap for your '88 LeMans. And if not, you can craft one yourself by drilling a hole and using the covered vent from another cap. Good luck, Clyde.

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