Adam Herrera says he listed his 2007 Toyota Tacoma on OfferUp for $13,000, when a potential buyer reached out.
"They wanted to meet. They were very interested. So they said they would come in from Riverside. So, I agreed to meet them here," said Herrera.
At an In-N-Out parking lot in Hesperia, Herrera says he met two men, plus a preteen boy and a toddler.
He popped the hood for one of the men while the other asked him a question at the back of the truck.
As Herrera was distracted that's when the preteen boy made his move -- as captured by his truck's dash camera.
"He opened up the oil-filler cap and he poured the bottle of water in the oil-filler cap then replaced the cap," he said.
Herrera said the boy then signaled to the two men.
"We went for a test drive. I drove about a mile down the road and it starts smoking. The truck starts smoking," said Herrera.
Back in the parking lot, Herrera again popped the hood of his truck to see if he could spot the problem.
"I crawled underneath to look at it," he said. "Another video shows one of the men reach into his crotch take out a bottle of oil and poured it on the motor and then into the overfill tank."
That's when he says the scammer made his move with an offer.
"He goes bad motor I buy it $5,000," said Herrera.
But something wasn't right. Herrera and his wife had just taken the truck on a long road trip to New York without any issues.
"I shook my head and I said I am not selling nothing you did something to my vehicle," Herrera told the men.
Realizing he had been taken for a spin, Herrera says he called the police and had his truck towed to the dealership where they were able to flush the water and clean out the oil.
The repair came to $1,500. Luckily his truck wasn't totaled and he eventually sold it.
"You got to keep an eye on people like a hawk," said Herrera. "You know these guys were expecting for me to be someone who needed the money to sell this thing to them for pennies on the dollar and I absolutely knew they did something to my truck."
The Hesperia Police Department is investigating.