DURHAM – First she smelled smoke. She and her daughter couldn’t quite tell where it was coming from.

Then Marie Cooper, traveling behind her husband, on the way to a dealership to trade in their two trucks Saturday afternoon, saw flames peek out from under the cab of Richard Cooper’s old Dodge.

“I said, ‘My God, he’s on fire, we’ve got to call him!'” Marie said Saturday night.

She reached him immediately on his cell phone. Despite pleas to pull over and the growing smoke, “he kept going until he could find a side road,” she said. “I thought, literally, he was going to blow up.”

Finally Richard hopped out, they backed away to safety and the truck went up in flames. While the Coopers tried to figure out where they were so they could call for help, nearby homeowners called for them.

The 1987 Dodge Dakota was engulfed when Durham firefighters arrived on Swamp Road at 1:21 p.m., according to Androscoggin County Sheriff’s Deputy Maurice Drouin.

Marie said her husband hadn’t noticed any smoke while he was driving.

“He thought it was the snow blowing around,” she said. “Thank God he got out. If he had stayed in there, he would have been toast.”

Marie, 37, and Richard, 61, bought the truck last fall to plow the driveway of their home in Auburn. There hadn’t been any hints of problems. It had been destined to be traded in, along with the truck she was driving, for a 2007 Dodge. Once the smoke cleared and the burnt hulk was towed away, they went on as planned to Bodwell Chrysler Dodge in Brunswick. She showed salesman pictures from the ordeal on her camera phone.

“We still got a trade-in. I showed the guys everything, you could see the flames in the picture. They just said, ‘Wow,'” Marie said.

She was shaken up and her daughter near tears, but her husband kept his cool.

“He stayed pretty calm,” she said, “but that’s his nature.”

Connie Footman contributed to this report