A 13-year-old boy discovered a car submerged in a Canadian lake last month — and in the process, helped cops close the cold case of a woman missing for nearly three decades.

Max Werenka spotted what looked like a vehicle sitting beneath the surface of British Columbia’s Griffin Lake in mid-August and decided to explore.

“I always like to question things,” the teen told CTV News in a report published Saturday.

Royal Canadian Mounted Police came to scope out the situation Aug. 21 — and Max dove into the lake to help, using a GoPro to capture footage of the overturned car, lying on the lake bed 15 feet below the surface.

Police divers returned three days later and found a person inside the 1980s-era black Honda Accord.

“When we initially heard someone was in that vehicle, my heart just sank,” said the teen’s mom, Nancy Werenka.

Cops were able to grab the car’s license plate, and traced it to 69-year-old Janet Farris, who went missing in 1992 — 14 years before Max was born.

“I couldn’t imagine for that many years, not understanding what happened to a loved one,” the teen said.

Farris, from Vancouver Island, disappeared 27 years ago on a solo road trip to Alberta.

Her son, George Farris, said the family now finally has closure and knows the “end of the story.”

Police raised the vehicle from the lake and are inspecting it for any clues to what went wrong — though they don’t believe Farris’ death was suspicious.

They praised Max for his “outstanding” detective work.

“The RCMP will probably be looking at this guy down the road for potential employment,” said Cpl. Thomas Blakney.