Washington-area gasoline prices hit their highest levels ever this week, continuing a spiral that has added an average of 31 cents to the price of a gallon of self-service unleaded gasoline since Iraq invaded Kuwait Aug. 2.

Self-serve unleaded averaged $1.41 a gallon in the Washington area, the American Automobile Association's Potomac branch said yesterday, up 3 cents from a week ago. Nationally, AAA reported, unleaded averaged $1.379, up 0.9 cents from last week.

The local price exceeded the previous record of $1.38, set in 1981, AAA said.

Experts say the rise in gas prices is likely to continue for some time, even though crude oil prices have headed downward in recent days, because oil companies have not passed through to consumers all of the increases in their crude costs.

The price of a benchmark barrel of high-quality crude oil rose 8 cents yesterday on the New York Mercantile Exchange, to $36.80, after being off by about $2 most of the day but recovering near the close. On Wednesday, the price dropped $2.17 a barrel, continuing a decline from a high of $41.15 last week.

At its current levels, oil is up 40 cents a gallon from its pre-invasion price, indicating that even with a 31-cent rise gasoline prices still must climb to catch up.

"Even if everything got better right now over in the Persian Gulf, we'd be facing rising prices for weeks to come," said AAA-Potomac spokesman Fred Carr. "Today when I talked to the stations, some of them were raising their prices."

The higher prices are evenly spread around the Washington area, AAA said, with District self-serve unleaded prices averaging $1.39 a gallon, suburban Maryland averaging $1.40 and Northern Virginia averaging $1.43. Carr said the highest price among the 60 local gas stations AAA surveyed was found at a station in Virginia that is charging $1.49 a gallon for self-serve unleaded.