The 1974 Datsun had a mashed front end, a dented door and an engine that self-professed experts in the crowd diagnosed as beyond repair. It also had a ring of people around its rust-stained fenders, eagerly bidding for the right to tow it home.

"There is such a thing as auction fever," said retired mechanic T. J. Smith, after the bidding for the dilapidated Datsun had finally stopped at $500. "People get carried away for a few minutes, then spend the next couple of weeks kicking themselves in the rear."

The Metropolitan Police Department's auction of abandoned and confiscated motor vehicles is a prime place to study that fever, described by another auction veteran as "auto eroticism." Held on the first Tuesday of each month at the department's nine-acre Blue Plains holding lot, the auction regularly attracts about 500 people who descend upon the rows of cars like treasure hunters at a giant garage sale.

"They're looking for small cars," said Police Lt. Douglas Cisell, "but they'll buy the big ones, too."

Cissell is the department's property clerk and , as such, the largest-volume used car salesman in the metropolitan area. Last week, Cissell, with the help of two professional auctioneers, sold 367 cars, three motorcycles, three mopeds and a tractor for prices that ranged from $20 to $8,750. He would not say how much money the sale brought to the District treasury.

"We don't want an armed robbery-type situation to develop here," cautioned Cissell, who has been overseeing the auctions for three of the 19 years they have been held at the Blue Plains lot. Before then, the auctions were conducted at Sixth and O streets NW, where a playground now sits. The predecessor to that lot was one at Sixth and School streets SW which closed in the early 1950s. The history before 1940 is vague, but police department officials claim the auctions are almost as old as the automobile.

"How long have police been ticketing and impounding cars?" Cissell asked rhetorically last week at the start of one of the largest auctions in department history.

More than 600 people, from as far away as Pennsylvania, came to the lot, which is across the street from the Blue Plains Sewage Treatment Plant on I-295. The gates opened at 8 a.m. By noon everything on wheels had been sold.

Most of the cars looked battered and abused. Some were abandoned on city streets after death from old age or accident. Many were left on impoundment lots by owners who judged them not worth the cost in towing and tickets to retrieve. The majority of those cars were bought by dealers in used parts or scrap metal like George Underwood, who runs a towing and scrap metal removal business in Forestville, Md.

"The ones I buy never hit the street again," said Underwood, who bought 46 cars last week. His two brothers, who each have their own scrap removal businesses, bought another 80 cars between them.

Even though most of the cars were sold to professional dealers, the majority of people at the auction were amateur bargain hunters, looking for pearls among the automotive swine. The most coveted was a 1979 Cadillac Coupe de Ville, which had been stolen from a man in California by his ex-wife and recovered in the District. Cissell said the owner had been notified twice that his car had been found. After 60 days without an answer, it became the District's property to sell.

At 8 a.m., when the lot opened for a pre-auction hour of inspection, the crowd examined the merchandise in more and less sophisticated ways. Some actually kicked tires. One woman went from car to car sniffing transmission fluid.

"That tells me if it's burnt," said Gladys Dial, of Northwest. "I also check the oil to see if it's dirty."

Because the prospective buyers are not allowed to start the cars, there is no certainty that they ever will. The more mechanically inclined buyers check spark plugs and pull fan belts. The rest bid on hunches and blind faith.

"It's like buying a pig in a poke. You never know for sure whether it's any good," said T.J. Smith, who was wearing a pith helmet, blue work clothes and a look of benign amusement. "Unless you know cars, you can lose your shirt."

The retired Navy Yard mechanic guessed that he had bought 35 to 40 cars in the 30 years he has been attending the police auctions. Last week he was only there to watch the show.

The auction began at 9:30 a.m. Within half an hour 50 cars had been sold. Among the first was a 1973 Vega for which 16-year-old Everett Barnes paid $180. The Eastern High School student admitted he wasn't the most patient buyer on the lot. He had gotten his driver's license just two weeks earlier and couldn't wait another 10 minutes to own a car.

"They'll be surprised at school," said Barnes, reving up the engine after one of the four locksmiths who work the auction made him a key for $15.

Belinda Wentz was more discriminating. The 21-year-old nurse had driven to the auction from Charlottesville, Va., that morning with her father. While most of the other buyers followed the selling processional led by one of two auctioneers who alternated after each row, Wentz stayed beside a 1978 Volkswagen Dasher.

"This is the only one I'm interested in," said Wentz. "I think a lot of others are, too."

The Dasher was parked bumper-to-bumper with the other auction favorite, the 1979 Cadillac Coupe de Ville. The two cars, representing opposite ends of the gas-guzzling scale, had attracted a standing-room-only crowd while the auctioneer, Irving Kamins, was still selling a battered, engineless police cruiser 15 cars down the line.

The Volkswagen went for $3,950 to two friends, recently from Afghanistan and now living in Silver Spring. Abdul Hamidi and Ahmad Mojadidi inadvertently provided the biggest laugh of the day when the auctioneer, also inadvertently, got them bidding against each other.

Bidding on the Cadillac started at $6,000. Just before that, auctioneer Kamins reminded the crowd of Officer Cissell's earlier announcement. "You've got to pay in cash. We don't take food stamps or checks, only dead presidents."

At $8,000 there were three bidders left -- a used car dealer from Brandywine, the owner of a limousine service in the District and a real estate broker from Alexandria. The crowd was jammed around the prize, watching the players for facial expressions and whistling at the spiraling ante.

When it was over, Ivan Jenkins, the Alexandria real estate broker, paid $8,750 for a car he had never started.

As the crowd moved off to bid on a Volkswagen bus without an engine, Jenkins sat in his new Cadillac listening to the radio, and Shelly Farber, a third-year law student at George Washington University put things in perspective.

"It proves America loves cars, old or new, whether they work or don't work." CAPTION: Picture 1 & 2, Cash is the only legal tender at the D.C. police department's monthly car auction. Bidders may inspect cars -- as Gladys Dial, of Northwest, does by checking transmission fluid dipstick -- but are not allowed to start the vehicles. Photos by James M. Thresher -- The Washington Post ; Picture 3, The bidding was feverish for this 1979 Cadillac. At the cry of "Sold!" and Alexandrian paid $8,750 for the prize. By James M. Thresher -- The Washington Post