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BMW Says Its Cars Need Fewer Oil Changes

October 15, 1998|JEANNE WRIGHT

Question: Highway 1 recommends changing my oil every 3,000 miles. However, I own a BMW with a service indicator and my dealer refuses to change the oil until all the service indicator lights are out, which is usually after 8,000 miles. Should I spend the extra money and get the oil change every 3,000 miles or stick with the indicator? --C.T.

Answer: Although many oil experts recommend ignoring manufacturers' suggested oil-change intervals and changing the oil every 3,000 miles, BMW insists that you should trust your service indicator.

You don't need to waste your money on an unnecessary oil change, says BMW spokesman Jack Pitney. The indicators, which have been a BMW feature for at least a decade, will accurately alert you when your car is ready for an oil change.

How many miles between changes depends on how and where you drive, Pitney says. General Motors goes even further than BMW, suggesting that owners of new Cadillacs can go 10,000 miles between oil changes.

Oil expert Norm Hudecki, former research chief at Valvoline Oil, agrees that how a car is driven can affect engine oil life. In addition, better oils, such as new synthetics, last longer than cheaper oils, Hudecki says.

As the miles accumulate, oil becomes contaminated with combustion products and minute amounts of engine metals, which eventually form sludge that reduces engine life. In addition,multi-weight oils lose their ability to control viscosity as they age.

Not all cars wear out oil at the same rate. A poorly designed or poorly manufactured engine will contaminate the oil faster than in a clean-running system.

Presumably, the engine in your high-priced BMW does not fall into that category. Yet the idea of saving money on oil changes after paying $30,000 or $40,000 for a car seems a bit of a stretch.

Question: I just got hit with a $400 brake job on my 1991 Ford Taurus. I couldn't understand a thing the mechanic said, but he told me my caliper stuck and caused all the problems. Almost the whole system had to be replaced. What is a stuck caliper?

--D.B.

Answer: A stuck caliper is a wrecking ball on your monthly budget. It is among the problems that can cause serious damage to a braking system, but it generally will not cause a catastrophic loss of braking unless many warning signs are ignored.

The caliper is a key player in the braking system, hydraulically squeezing the brake pads against the rotor like a powerful clamp. After you release your foot from the brake pedal, the caliper is supposed to allow the pads to move away from the rotor, also known as a disc.

A stuck caliper to some extent keeps the brakes on all the time. It rapidly wears out pads. Because you aren't expecting such rapid brake wear, the problem is often compounded because when the pad is fully worn, the metal backing plate digs into the smooth surface of the disc and ruins it in most cases.

This is what happened to you. I would guess that the reason your bill was so high was that both the caliper and the disc had to be replaced. I am guessing that the mechanic also suggested that you make the same repair to the opposite side of the car to balance the brakes and prevent another stuck caliper.

That's all standard and good advice, though some risk takers would doubt the need to replace the opposite caliper and rotor. The $400 price was more than fair.

A stuck caliper sometimes causes a car to pull to one side. Once the pads are fully worn, you should hear a modest grinding sound as metal rubs against metal.

A good mechanic should inspect brakes at each oil change, which should be done as often as every 3,000 miles. Such periodic inspections are another benefit of frequent oil changes. With any luck, you should have been able to catch the problem before you destroyed the rotor. You could have saved 75% of the repair.

One way to check for a stuck or binding caliper is to have a mechanic attempt to rotate the front wheels by hand when the car is up on the rack, immediately after the brakes are applied. If he or she has a great deal of trouble rotating them, the pads are probably not disengaging from the rotor.

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Jeanne Wright cannot answer mail personally but will attempt to respond in this column to automotive questions of general interest. Write to Your Wheels, Business Section, Los Angeles Times, Los Angeles, CA 90053. Via e-mail: highway1@latimes.com.

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