In an effort to cut back on maintenance costs, repairs and other automobile expenses, the Metropolitan Police Department has bought 59 Plymouth Volares as replacement vehicles, the first compact cars in the department's 488-vehicle fleet, police said.

The department also purchased 70 intermediate-size Ford LTD-2s as part of the replacement package.

Police Chief Burtell M. Jefferson said the purchase of Volares and LTD-2s in the same package is the first time the department has accepted a split bid on its automobiles.

The arrival of the new police cars comes about a year and a half after the federal General Accounting Office criticized the District government for not buying police cars through the federal government.

At that time, the GAO said, the District could have saved $75,000 on 260 police cruisers if it had combined its order for cars with that of other agencies to benefit from volume purchase savings and bought compact cars.

Police Inspector George P. Day, director of the department's fleet management division, said this year the department placed its order with the General Services Administration. Chrysler and Ford offered the lowest bids, he said.

"We're looking for vehicles that have good services, low on repairs, and good acceleration," Day said, "but we don't need the heavy speed of the larger engines."

Neither Jefferson nor Day would estimate how much the department hopes to save from the purchase of the Volares and LTD-2s, which cost about $4,600 each.

But a recent issue of Consumer Reports, a magazine published by Consumers Union, which bills itself as a guide for consumers, said Volares had predicted incidences of repairs that were "much worse than average for the first two years of ownership. Trouble spots have been the body, fuel system, as it affects engine stallings and hesitation, and brakes."

Consumer Reports rated the Ford LTD-2s as "average" in terms of predicted repairs.

The 318-cubic-inch V-8 Volares and the 302-cubic-inch V-8 LTD-2s will replace some of the department's Plymouth Furies and Ford Torinos, police said.

The new cars come with dual mirrors, air conditioning, radial tires, rear window defrosters and what Day called a "law enforcement package - a heavier transmission and drive train." They will be used both as scout cars and unmarked cars, police said.