DETROIT — Dale Fortin is getting a new kind of customer at his Detroit auto repair shop, customers who have not just been in a fender-bender or had a windshield smashed by a rock.

The soaring price of crude oil has turned gas tanks into a cache of valuable booty, and Fortin has replaced several tanks punctured or drilled by thieves thirsting for the nearly $4-a-gallon fuel inside.

"That's the new fad," said the co-owner of Dearborn Auto Tech in Detroit. "I'd never seen it before gas got up this high."

While gas station drive-offs and siphoning are far more common methods of stealing gas, reports of tank and line puncturing are starting to trickle into police departments and repair shops across the country.

Some veteran mechanics and law enforcement officers say it's an unwelcome return of a crime they first saw during the Middle East oil embargo of the early 1970s.

Yesterday, gasoline prices rose to a record national average of $3.962 per gallon for regular, according to AAA's Fuel Gauge Report.

Given their height, Fortin said pickup trucks and sport utility vehicles are more vulnerable to thieves, who puncture the tanks and use a container to catch the fuel.

Plastic tanks are typically the target, he said, since there is less chance of a catastrophic spark, and they are easier to drill into.

A design change may also be contributing to the preference for a drill rather than a syphoning hose. The tanks in many vehicles now have check balls, which prevent spills in a rollover accident. They also make siphoning more difficult.

In recent weeks, police in Denver arrested two suspects in connection with about a dozen cases of damaging tanks and stealing gas.

Denver Police Detective John White sees this "new way of siphoning gas" as a bigger problem.

"What made this particular method so dangerous and concerning for us was the way in which they were doing it — using cordless drills to puncture holes in these tanks," he said of the rash of cases his department has investigated this spring. "The heat, friction generated could have easily sparked a fire. It just made for a dangerous situation for the suspects and the community."

Tank puncturing has yet to reach the radar screens of law enforcement organizations such as the National Sheriffs' Association, or the Automotive Service Association, a group that represents independent garage operators.

Still, at least one insurance company has taken notice: AAA Mid-Atlantic issued a press release this month that cited a case in April in Bethesda, Md., involving a thief who broke the fuel line underneath a car and sapped 5 gallons of gas. Montgomery County police said a bus in the same parking lot had 30 gallons of diesel stolen.

"These are crimes of opportunity," said AAA spokeswoman Catherine Rossi. "Right now, some people think that stealing gas is a way to get rich quick. It becomes a question of whether you're leaving yourself open to the possibility that someone can get to your car without being seen."

The cost of replacing a metal tank on passenger vehicles is between $300 and $400, and the plastic tank common on newer vehicles would be at least $500.

Troy Police Lt. Gerry Scherlinck said his suburban Detroit department this month received a report of a stored motor home whose tank was siphoned and drained of 50 gallons of gas. They also had several incidents last year in industrial parks where the gas tanks of vehicles were punctured.

"Gas is liquid gold these days, and has been for the last year-and-a-half," Scherlinck said. "I would anticipate seeing more of these kinds of incidents as the price continues to go up."