Automania/Repair & Maintenance

AUTO QUESTIONS AND ANSWERS FOR WEEK 29

by Bob Hagin

Q. I have a 1992 Chevrolet Cavalier two-door sedan. Almost exactly three years ago the alternator went out. Last month I had to have another alternator installed as the replacement failed. Is this typical for this car or did I get a lemon? The car now has a little over 67,000 miles on it. B.C. Virginia Beach, VA

A.There's been lots of complaints about General Motors cars and trucks of that era having multiple alternator failures. There doesn't seem to be any rhyme nor reason to the failures, but I suspect it's related to the alternator's grounding system. After a few years of jiggling through life, ground connections can loosen up a little, acquire a bit of corrosion and develop an intermittent open circuit. This will eventually cause it to fail. Have your mechanic check and clean all the electric connectors around the alternator and make sure that the engine is well grounded too. Also have the mechanic make sure that the alternator mounting brackets are tight and corrosion-free.

Q. When installing a new battery in my 1967 Buick Riviera, the cables were crossed, sending up a cloud of white smoke from underneath the engine. From that moment on, even when the cables were connected correctly, there was nothing - no lights, no horn, no ignition. What happened? What do I do now? V.M. Mercer Island, WA

A. Unless you're fairly adroit mechanically, you'd better seek out a mechanic (preferably one who specializes in electrical work) who isn't intimidated by the idea of rewiring an automobile electric system. When you installed the negative cable to the positive terminal of the battery, you put full amperage to the ground circuit of the wiring loom. The white smoke you saw was the insulation melting and burning on the dozens of wires that are in the system. When the insulation melts and burns, it allows the various wires that share the loom to make a direct, solid connection which adds to the conflagration. Separating the wires and rewrapping them would be a task for Hercules and replacing the damaged connections wire-by-wire could lead to insanity. The latest issue of Hemmings Vintage Auto Almanac has several pages of suppliers who specialize in replacement vintage electrical parts as well as half a dozen listed under Wiring Harnesses. Crawling around in the engine compartment and under the dashboard of a 32-year old car isn't a pleasurable task (I've done it) but there is no other way. Check a wiring diagram for your Riviera and see if there's a fusible link in the circuit somewhere. That would be a good place to start. Remember: the big post on the battery is Positive and the small post is Negative.

Q. My 1991 Toyota Camry has a 2.5-liter V6 engine and an automatic. I bought it new and it now has 52,000 miles. At 21,000 miles it developed a knocking noise under a load. I took it to the selling dealer and the service manager said to keep driving it to see if the noise got any worse, since I still had a Toyota Extra Care warranty. At 42,000 miles, the noise was worse and the dealer's shop checked the crankshaft main and connecting rod bearings. The main bearings were OK but the bottom rod bearing shells had a quarter-moon shaped wear pattern that went down to the hard metal backing. The crankshaft was OK and the bearings were replaced. Could this happen again on an engine with such low mileage? D.S. Sacramento, CA

A. There were Toyota and Lexus models that shared that engine and they did have some rod bearing problems. In most cases, the entire short block was replaced rather than simply install new bearings. I've seen the problem and it looked like classic "cocked" rods. I never got to check the rods for straightness, but I always thought that Toyota pistons were a little short which could have exacerbated the problem.