Adulterated Fuel Leaves Motorists’ Cars Sputtering : Gasoline: Mobil Oil says rust inhibitor was mistakenly added at loading terminal. The firm has paid for repairs to damaged engines.

Douglas Johnston knew he had a problem when he pushed down the accelerator of his 1976 Mercedes convertible one day about a month ago.

“It’s like half the cylinders weren’t working,” said Johnston, a Hermosa Beach resident. “The Fourth of July weekend was shot, because I was afraid to take it anywhere.”

At about the same time, Greg Wilson found that his high-performance 1989 Ford Taurus was losing power during his daily commute from his home in Huntington Beach to his job in Manhattan Beach.

“It would act like you were starting to run out of gas,” Wilson said.

Johnston, Wilson and hundreds of other South Bay motorists had unknowingly received Mobil gasoline with a hidden feature--a double dose of rust inhibitor.

The problem was traced to a loading terminal at Mobil’s Torrance refinery. Rust inhibitor was mistakenly added to the gasoline instead of detergent, Mobil spokesmen said.

Fuel systems rebelled. All over the South Bay, cars that had tanked up with the contaminated gas began shuddering, sputtering, stalling.

Mobil Oil Corp. announced June 28 that it had accidentally distributed tainted gas and promised to reimburse motorists for damage caused by the product.

Now the oil giant is paying to clean the fuel systems of an undetermined number of cars. James Amanna, a spokesman at Mobil’s Fairfax, Va., headquarters, on Thursday refused to make public the number of cars repaired or the total bill footed by Mobil.

That information is “immaterial,” Amanna said. But he did confirm that hundreds of cars were affected, primarily in the South Bay area.

“The story is, from our standpoint, that we responded to each complaint,” Amanna said.

Random inquiries at 12 South Bay dealerships and repair shops this week found more than 300 cars serviced for the Mobil gas problem, with bills ranging from $150 to $500 or more per car. Work ranged from simply cleaning the fuel lines to replacing damaged fuel pumps.

The faulty fuel was sold at 98 Mobil stations in the Los Angeles area, Amanna said. The stations were in the South Bay, Long Beach, Santa Monica and other parts of Los Angeles and Orange counties. All stations have carried clean gasoline for the past month, Amanna said.

Some service managers this week praised Mobil’s response to the problem.

“Mobil was very gracious through this whole deal. They were very, very easy to deal with,” said Bill Messenger, service manager at Torrance Nissan Inc., which repaired 34 cars with the gasoline problem.

“Everything we suggested to have done, they agreed with,” said Thomas McElhone, owner and manager of South Bay Imported Cars in Redondo Beach.

Some repair shops were flooded with customers complaining of cars hesitating and stalling.

“The first part of the month, it seemed like we were busy all the time, every day. . . . We were doing seven or eight a day,” said service manager Joe Dalven at South Bay Toyota Inc. in Gardena. The firm, which repaired more than 100 cars, arranged to do the work and then be reimbursed by Mobil’s insurance company.

Wilson, whose Taurus suffered problems, is parts and service director at Manhattan Ford in Manhattan Beach, which worked on 35 to 40 cars.

Wilson’s Taurus cost more than $300 to repair. But some bills were higher. One repair bill at Manhattan Ford totaled $1,362, for a car with a damaged fuel pump and fuel injectors, Wilson said.

Most cars needed less work: a drained gas tank, flushed lines and new filters.

Wilson said he is pleased with how repairs were handled.

“Sure, no one likes the inconvenience,” Wilson said, but “I feel real good, because Mobil was real fair about it.”

Johnston paid $170 to have his Mercedes repaired at Folded Wings Ltd. in Hermosa Beach.