Dear Tom and Ray:

I have an elderly car, a 1987 Pontiac 6000. I took it in for an oil change the other day, after I noticed a slight clicking noise. At the oil-change shop, the fellow said he couldn't change my oil because the clicking sound meant that the bearings were bad, and changing the oil would wreck the engine. He said my current oil was "lighter," because it was old. He said new, thicker oil would increase the pressure and make the engine "blow." Is he right? -- Debbie

Tom: No. He must be one of those M.D./Ph.Ds they're hiring at all those quick-oil-change joints these days. He probably knows enough to know that something is wrong with your engine, and he's afraid that if it does blow (by coincidence) three weeks after he changes your oil, you'll come back and blame him ... .like his last eight customers have.

Ray: In reality, what you're hearing is probably noisy lifters due to low oil pressure. And thicker oil would only help the oil pressure at this point.

Ray: If anything, it's more likely to "blow" with lighter-weight oil in there than with heavier-weight oil. So don't go back to this guy.

Tom: But before you go dumping some 80W-250 sludge in the crankcase, you should go to a more knowledgeable mechanic and get your oil pressure tested. Hydraulic lifters are situated far away from the oil pump, and when they make noise, that's usually an early warning sign that there's not enough oil pressure.

Ray: If you test the oil pressure and it's good, then you can rule out a bad oil pump and bad bearings, and look instead into the possibility of a worn cam shaft, a bad timing chain, or even something as simple as a bad lifter or a sticky valve.

Tom: If you really do have low oil pressure, there are three likely causes. The most obvious is that you don't have enough oil in there, but let's assume you've checked that. The second possibility is a bad oil pump. The third, and grimmest, possibility is that your bearings are worn out. And if it's bearings, you've got a tough decision to make.

Ray: Well, not that tough. It's just a Pontiac 6000, remember. But you do have to decide how much you love this car, Debbie, and how long you want to keep it.

Tom: If it's in good shape and you're committed to it for the long haul, you can have the engine rebuilt for a couple of thousand bucks.

Ray: But if you're ready to get rid of it, or just want to limp along for another six months or so while you look for another car, then you can just put some 20W-50-weight oil in there, and keep driving it until it croaks. Good luck, Debbie.

To buy or not to buy -- options, that is. Are options worth what you pay for them, or are you better off just going with the basics? Order Tom and Ray's pamphlet "Should I Buy, Lease, or Steal My Next Car?" to find out. To order, send (check or money order) to Ruin, P.O. Box 536475, Orlando, FL 32853-6475. You can also order online.

© 1997 by Tom and Ray Magliozzi and Doug Berman Distributed by King Features Syndicate, Inc.

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