Big sales of diesel cars in US generate second looks

General Motors got more than it bargained for when it launched its 8-cylinder diesel engine a few years ago. Even though GM denies any basic flaw with the cars -- some 500,000 of which have been sold in the last severatl years by GM -- thousands of motorists report major difficulties ranging from leaky head gaskets and oil leaks of faulty fuel systems.

In a poll of 500 owners of '78-model Oldsmobile diesel automobiles a year ago , California-based J. D. Power & Associates, an automotive-market research firm, found that at least 75 percent had at least one engine complaint about their cars.

Now the New York owner of a '78-model Olds has filed a class-action suit against the big US automaker which asks, among other things, for $12 million in damages from GM. New York dealers who sell GM diesel-engine cars are named in the litigation as well. The GM-built diesels have long had a water problem with the fuel.

With the latest flap over the GM diesel turn off consumers on the high-mileage engine?

Probably not, given the importance of the engine toward meeting future fuel-economy goals for the automobile as well as GM's response to the complaints.

Several months ago GM finally faced up to its nagging diesel dilemma by taking on the huge cost or repairing the cars already in consumer hands. Further, it made significant improvements in the 1980-model diesel engine which is built by the Oldsmobile division of GM.

More than half of all diesel cars sold in the US this year are built by GM.

Why a diesel engine in an automobile?

The big advantage, say engineers, is the 25 percent better fuel economy it provides over a gasoline engine. Automakers count on the higher-mileage capability of the diesel to help them meet the increasing corporate average fuel economy (CAFE) standards in the mid-and late 1980s.

The reasons for the improved efficiency of a diesel are the sharply higher compression ratio (22 to 1 in the GM diesel compared with 8 or 8 1/2 to 1 in most gasoline-fueled engines) and the absence of carburetor throttling, reducing engine friction.

"The diesel process enables more complete fuel utilization," says E. M. Estes , president of GM and an engineer.

All automakers have major plans for diesel cars in the future, unless, of course, the diesel engine is ruled off the road by supertough federal emissions legislation which the diesel could not hope to meet. The diesel engine is especially high in oxides of nitrogen and particulates, or soot.

Ford has a deal to buy turbodiesel engines from West Germany's BMW when its new diesel plant goes into operation in Steyr, Austria.Ford earlier had opted out of a contract with Cummins in the US. Ford also will get small-size diesels from its Japanese affiliate, Toyo Kogyo, maker of the Mazda.

The diesel dilemma at GM could have a serious impact on the marketplace, not only for GM but for competing carmakers as well. If the unhappy notoriety continues, it could turn motorists off on the engine.

American motorists now are buying the highly rated Volkswagen diesel Rabbit (both pickup truck and sedan) and Dasher in high numbers as well as the Audi, Volvo, Peugot, and Mercedez-Benz. In the future they'll have the added choice of diesel-powered Renaults, Fiats, and Chryslers, plus the Japanese.

Daimler-Benz, for one, has no plans to slow down output of its highly rated diesel fleet. About half of all Mercedes automobiles now have diesel engines under the hood. In the US the number is closer to 75 percent.

"We see a growing emphasis in favor of the diesel engine," asserts Dr. Gerhard Prinz, chairman of Daimler- Benz.

"In our opinion the diesel engine has a bright future."

Last year some 270,000 diesel cars were sold in the US in contrast to 37,000 only two years before. GM has long predicted that by the mid-1980s its diesel-engined cars will account for at least 15 percent of total retail sales, or close to 1 million units a year.

GM is not a newcomer to the diesel engine, by any means. It has a long history of building high-output diesels, not only for turcks and buses, but for locomotives as well. Thus, it didn't expect any major problems when it decided to convert two standard gasoline engines to diesel fuel. VW did the same thing with the Rabbit. However, the larger-size diesels have far tougher, heavy-duty components in comparison to the much-lighter-weight, passenger-car engine.

Indeed, the automaker saved not only money but time as well. GM was able to put a diesel engine into the traffic stream in record time and at far less cost than would have been possible with a diesel engine that was engineered and built from scratch.

GM firmly denies it cut any corners in making the switch from gasoline to diesel. Nonetheless, the carmaker is paying a price it had not expected to pay.

While the diesel engine automobile has caught the eye of the motorist and its pluses are well known (higher mileage, less maintenance, and cheaper fuel), there is a negative side as well. For example, a diesel-engine automobile costs far more to buy than one with a gasoline engine, the engine oil has to be changed more often, it is slower and sometimes harder to start in cold weather, and acceleration is less. Also, diesel engines are more noisy than a conventional gasoline engine and they smoke and smell to boot.

Despite it all, however, motorists generally are intrigued with the concept and the company it keeps.

The high-priced Cadillac Seville, for instance, comes with a diesel engine as standard although a gasoline engine is available as well.

Whether the GM diesel flap will harm its chances in the future is still to be answered. The fact is, the automaker is trying hard to meet the issue head-on.