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Automania/Repair & Maintenance
AUTO QUESTIONS AND ANSWERS FOR WEEK 16 YEAR 2000
by Bob Hagin
Q. I have a 1998 Jeep Grand Cherokee that has the 5.2 liter V8 engine, an automatic transmission and four-wheel drive. It has 55,000 miles on it. It's a company car that is used to pull a sports boat as well as for daily transportation. At around 30,000 miles it developed a whine from somewhere in the driveline and I assumed that it was the rear end gears. The dealer's shop reported that the whine was coming from noisy bearings in both the front and rear differentials and replaced all of them. At 50,000 miles the noise was back and again the dealer's shop replaced bearings in both axles at a cost of $1200. According to the invoice, none of the gears themselves were replace, only the bearings and the various seals. My question is whether the first job was done incorrectly which necessitated the second or if it's a flawed design that will cause the bearings to get noisy at regular intervals.
A. I'm not sure if anyone at any level knows exactly what causes those noisy differentials in 4X4 Jeep Cherokees but the internet services that provide access to customer complains on the subject lists lots of them. It could be faulty original assembly or even housing castings that weren't thoroughly cleaned and allowed grit to get into the bearings. If it could be pinpointed, the technician wouldn't have to replace all the bearings every time but it's usually done as a safety measure since minute metal shavings from a bad bearing can cause its neighbor to fail prematurely. I haven't been able to examine any of the parts that have been removed but I'd bet that a chemical analysis of the lube oil would come up with an answer. Better be prepared for an ongoing problem.
Q. Recently I was fortunate enough to acquire a 1982 Cadillac Eldorado Biarritz with white leather interior. It had belonged to a 92-year old friend who drove it very infrequently and always kept it garaged. It does not have a single scratch on it and has only 60,000 miles. I know that I will enjoy it for many years. Inasmuch as it is as old as it is, it is very difficult to get any information on it. Perhaps you know how I could find or make copies of the sales brochures that were put out with this car. Or perhaps you can tell me where I could get some specification sheets on or news media reviews.
A. I assume that you're looking for general information like magazine road tests of that era as well as promotional brochures, etc. Judging by the tone of your letter, it doesn't look like you want do-in-yourself repair manuals. Hemmings Vintage Auto Almanac is my old standby for this kind of stuff and the latest version (Number 11) shows that the Cadillac LaSalle Club has chapters all over the country for technical support as well as social contacts. You can check out the club at its website, www.cadillaclasalleclub.com. It's a very impressive site and should give you the information you want. The Hemmings Auto Almanac also lists three pages of auto literature dealers who have brochures and catalogs for cars I've never even seen, in some cases. A copy is around $12 and it provides lots of reading entertainment even if you don't buy anything.
Q. The maintenance schedule for the '91 Toyota Tercel I just bought calls for the valves to be adjusted every 15,000 miles. I remember this from my high school auto shop days but that was long ago and I thought that auto valves were self-adjusting now. Apparently it's an involved procedure. Is it really important and if it is, can I do it myself?
A. If valve adjustments are ignored, the valves tend to burn up. If you're patient and have small hands, you can probably do it your self on your Tercel but it's a miserable job. The adjusters are tiny and hard to get to.
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