A Northern Virginia automobile dealer testified yesterday that Abe Pollin, the principal owner of the Washington Capitals, agreed to sell him the hockey team in March 1980, then told him in a telephone call days later there would be no sale.

Jacques Moore, owner of Moore Cadillac Co. near Tysons Corner, said in Prince George's Circuit Court that on March 7, 1980, he and Pollin shook hands on a sale of the Capitals for $5 million. Xavier Aragona, an attorney for Moore, testified that at the meeting Pollin told Moore, "You have a deal."

Pollin, who also is general partner in Capital Centre and owner of the Washington Bullets, angrily denied Moore's statement. Asked if he had agreed on a price to sell the team to Moore, Pollin said emphatically, "I absolutely did not . . . I don't ever break my word when I shake hands."

However, Pollin said he did offer to sell the financially struggling team to Moore for $4 million in December 1981. Aragona said Moore rejected the offer because it was tied to possible cable TV interests that Aragona said Pollin wanted to control.

In response to a question from The Washington Post in the summer of 1982, Moore denied having made a deal involving the sale of all or part of the Capitals.

Testimony was concluded yesterday in the 20th day of the trial involving Pollin and Arnold Heft, a limited partner in Capital Centre. In his civil suit, Heft alleges that Pollin, through several June 1982 adjustments in license agreements between the arena and the Bullets and Capitals, improperly diverted money from the Centre to the teams. Pollin testified the license practices unfairly hurt the teams and benefited the Centre.

Heft asks the adjustments be rescinded and an accounting of their effect be made. Attorneys for both sides have until May 15 to submit documents and briefs to Judge Albert T. Blackwell Jr., who then will hear oral arguments May 21 before rendering a decision.

In his second day of testimony, Pollin recounted several negotiations with Moore and others in the early 1980s to sell the Capitals, Bullets and the Centre. He said he rejected one offer by Moore to sell the three for $38 million.

"The mortgage on the Capital Centre was $19 million," Pollin said. "The Capitals were worth a minimum of $4 million and the Bullets $8 million. That would have left $7 million in equity for the Capital Centre."

In documents entered during the trial two weeks ago, it was revealed that during their tenure at Capital Centre, the Capitals had suffered $22.8 million in cash losses as of June 1984 and the Bullets about $4.1 million. The arena, meanwhile, had a net profit of $8.6 million, the documents said.

Pollin and Moore testified yesterday to having a series of negotiations over several years, but characterized them differently. Moore said his December 1979 offer to buy the Capitals for $2 million to $4 million was a starting point in negotiations. Pollin termed the offer "absolutely ridiculous" and "a slap in the face."

Pollin, noting he had paid $6 million for the team and subsequently had put in another $20 million of his own money, said he would have wanted an offer of "$6 million to $8 million" at that time. "The whole world knew the team was for sale, but the offer was an insult," Pollin testified.

By 1981, he said, he had lost another $6 million in the team and was willing to sell it to Moore for $4 million. Pollin did not say if any mention of cable television was made in connection with the offer.

Moore testified that although he was told in late December 1979 that the Capitals were not for sale, he and Aragona continued to have contact with Pollin and David Osnos, general counsel for the teams and Capital Centre. Moore said a meeting was set up among himself, Pollin and their attorneys in Osnos' office in downtown Washington.

Moore said the meeting lasted "a couple of hours." He said he initially offered $4 million for the team, but after another hour of negotiations, raised his offer to $5 million, which Pollin accepted.

"Mr. Pollin and I shook hands on it," Moore testified. "He asked me one additional favor -- that he could go home and talk to Irene (Pollin's wife)."

Three days later, Moore said, he received a call from Pollin. "He said he and Mrs. Pollin had talked it over, that he was not a quitter and that he would try to see it through again."

After retaking the stand, Pollin maintained "no specific price" was mentioned at the March 7 meeting and "there was no offer made" by Moore.

"You really didn't want to sell the team, did you, Mr. Pollin?" asked Stephen Grafman, one of Heft's lawyers.

"That is absolutely incorrect," Pollin said firmly. "I wanted to sell the teams, definitely . . . I didn't want to sell the Capital Centre, but if I had to I would have, to sell the Capitals."

Aragona, testifying regarding Moore's negotiations with Pollin, said, "Mr. Pollin kept flip-flopping. We didn't know what to do. There was no sense of hostility between me and Mr. Osnos, or even with Mr. Moore. The problem was Mr. Pollin."

In Pollin's December 1981 offer to sell the team for $4 million, Aragona testified, "He intertwined this with a cable-TV deal. We would have wound up with the donkey's tail and he would have gotten the donkey."