When portrait painter Charles Merill Mount rented what he thought would be his "dream house" in Arlington in 1977, he recalls, he was surrounded by soaring oak and poplar trees and disturbed only by the robins and orioles swooping low past the azaleas.

Five months after Mount had unpacked the last of his belongings, what he remembers as "hundreds" of enormous earthmoving tractors began digging away the woods in front of the driveway, beginning construction on the long-delayed Interstate Rte. 66.

"There was a fleet of trucks all day long, from seven in the morning until 4.30 in the afternoon, one every 30 seconds. They would drop their dirt and then leave," said Mount, 50, who has written books on artists John Singer Sargent, Gilbert Stuart and Claude Monet.

"After a year of that it began to get bad," Mount said in the slightly British accent picked up during the 17 years he lived in Europe, including England, France, Italy and 11 years in Ireland. "The pile drivers began arriving in the morning, and they worked right in front of the living room window."

Last week Mount filed a $100,000 suit in U.S. District Court in Alexandria against the owners of the house at 6923 Williamsburg Blvd., claiming that they failed to inform him about the pending construction of the superhighway.

Mount contended in an interview that the construction disturbed his peace of mind, which he needs to paint portraits such as the ones he has done of local society figures as well as political figures including First Lady Rosalynn Carter and former U.S. Sen. James O. Eastaland (D-Miss.).

Warren W. McLain, attorney for William and Nancy English, defendants in the suit, said yesterday his clients "couldn't have told Mount about the start of the highway because they didn't know when construction would begin. I've lived in Arlington all my life and the state has been buying property for it since I was in the fourth grade. Construction has always been held up by lawsuits. My clients have always fulfilled their obligations," he said.

McLain also said that a motion he filed in Arlington General District Court in a rent dispute with Mount preceded by about two months Mount's filing of the federal suit. McLain said Mount has failed to pay rent on the home for "six or seven" months and that the last check the Englishes received from the artist bounced.

"We contend he owes us about $3,000. That case is now set to be heard June 6," McLain said.

Mount, who said the rent for the nine-room home is$450 a month, concedes "there is a dispute between us, but they breached their contract by not telling me about the raod (I-66)."

In his own suit, Mount alleges that English "frivolously" sued him, altered his checks, let air out of his tires and set dogs loose "to chew plaintiff's newspapers and upset his garbage."

McLain denied all allegations except the one that his clients filed suit, which he said is serious because it involves money his clients need to pay the mortgage.

No trial date has been set for the federal court suit, which Mount, who says he is a graduate of the Columbia University Law School, drafted himself.

Several weeks ago Mount filed a separate suit in U.S. District Court in Washington against the University of Mississippi Foundation, claiming it owned him $12,450 for a portrait he had made of Eastland.

The portrait now hangs in the Dirksen Senate Office Building; a smaller version is at the University of Mississipi in Oxford. A spokesman for the foundation denied the extra money is owed. CAPTION: Picture, Charles Mount indicates I-66 construction near front of rented Arlington home. By James A. Parcell-The Washington Post