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Battery, alternator parts do wear out

2006 Buick Rendezvous

2006 Buick Rendezvous Credit: © General Motors

Dear Doctor: The battery light comes on intermittently on my 2006 Buick Rendezvous. The mechanic tested the original battery and it was in need of replacement. He put the car on the scan machine and told me there was some vague and confusing information regarding this problem, as well as with the voltage regulator. He told me if the battery change didn't work then I should replace the alternator -- at $350. What should I do? Tom

Dear Tom: Your car is six-years-old and parts do not last forever. The voltage regulator is an internal part of the alternator. The alternator is also subject to an extreme amount of heat, especially in the hot summer months. Have the technician check the battery under a load test as well. Next have the charging system checked under full load conditions. If you do replace the alternator then I suggest using a Bosch brand. I have a 98-percent success rate and it comes with a two-year national warranty. If the battery fails the load test, then go with the Interstate brand (get the highest cold cranking series available). Again, this is a good battery with national warranty.

Dear Doctor: Why does my 1999 Ford Ranger set the "check engine" light for right bank lean every October when they change the gas formulation for winter and then goes off in April when they reformulate the gas for summer use? It has happened for the last 5 years. I am baffled. Carl

Dear Carl: In the fall the gasoline formula in the Snow Belt region is changed for easier engine starting below 32-degree temperatures. The higher the gasoline octane the more spark is needed to fire up the gas and start the engine cold. The reformulation are additives added to ease the cold start-up and cold drivability. Now to your lean condition -- it may have nothing to do with the gas reformulation. I would look at a scan tool and see when the lean condition occurred. The most common fault I find is the small intake seal at the bottom of the plastic intake manifold. If the lean condition happened at cold idle, then the seals are the problem. If the lean condition happened under driving conditions, then look at what the oxygen sensor reading was at time of check engine light illumination. The fuel pressure and external fuel filter should also be checked, if equipped.

Dear Doctor: I purchased a certified pre-owned 2007 GMC Acadia, which now has 74,000 miles. On a recent trip I had problems with the tranny shifting sluggishly on mountain roads. On the return trip 10 miles from home the tranny blew. I had it towed to my local dealership where they replaced a gasket and basically rebuilt the transmission. Since then I find the shifting very sluggish around 35-40 mph. The service manager and mechanic state this vehicle equipped with six-speed transmission is working properly. What's your opinion? Susan

Dear Susan: It is not uncommon for transmission failure on these six-speed electronically controlled transmissions. There have been a lot of transmission issues on GM vehicles, as well as on other automakers vehicles, too. As for the sluggish shifting feel the technician says is normal; it may very well be. I own a 2010 Chevrolet pickup truck with a six-speed, which was also a sluggish-feeling transmission. I bought a reprogrammer from Summit Racing and this made a big difference. You can buy any brand reprogrammer. It is a simple download installation using the ALDL plug under the left side of the dash. The program can also be removed if you ever have to bring the car back to the dealer for any additional transmission work.

Dear Doctor: My brother-in-law has a 2000 Volvo V40 station wagon with an automatic transmission. The key has been getting stuck in the ignition. After a service adjustment on the shift console, the key cannot be removed. The technician didn't have a clue as to why this has happened. How should he go about getting the key out? Andy

Dear Andy: The first step is to see if the fault is in the safety shift interlock or the ignition key cylinder. We have had a few of these Volvo's with ignition cylinder problems. The technician who adjusted the shift linkage may not be familiar with the Volvo system. A dealer or import shop could be your best bet. -- Junior Damato, Motor Matters

Junior Damato is an ASE-certified Master Technician.

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