Anyone selling a car privately is being urged to keep their wits about them, as reports grow of a particularly underhand scam designed to knock thousands off a vehicle’s value in minutes.
The so-called “Dirty Oil” scam is targeting sellers using platforms such as AutoTrader, eBay and Facebook Marketplace—and it relies less on technical skill than on timing, distraction and a bit of theatre.
The set-up is simple enough. A prospective buyer arranges to view a car, often arriving with a second person. They appear keen, knowledgeable, and ready to do a deal.
Then comes the distraction.
While one keeps the seller occupied—asking about paperwork, suggesting a test drive, or simply making conversation—the other interferes with the vehicle. Typically, that means introducing oil where it shouldn’t be: into the coolant reservoir, or onto hot engine parts.
What follows can look convincing. Within a short time, the engine begins to smoke heavily, sometimes dramatically. The “buyers” then step in with a diagnosis—usually something along the lines of a blown engine or catastrophic failure—before offering a sharply reduced price, often a fraction of the original asking figure.
It’s a pressure tactic, designed to catch sellers off guard and push them into a quick decision.
There are, however, some clear warning signs. Buyers insisting on attending in pairs, one lingering near the engine bay while the other talks, or sudden, unexplained engine trouble during a brief viewing should all raise suspicion. Claims of expensive repairs without any proper inspection are another tell.
The advice is straightforward, if not always easy to follow in the moment. Never leave potential buyers alone with the vehicle. Keep it in sight at all times, particularly if the bonnet is open. Having someone else present can also make a difference, reducing the chances of distraction.
A quick check before and after any viewing can help too. Look for signs of tampering—oil where it shouldn’t be, or unusual residue in the coolant tank. Even taking a photo beforehand gives you something to refer back to if needed.
Above all, trust your instincts. A well-maintained car doesn’t typically fail without warning, and sudden, dramatic smoke should be treated with caution rather than panic.
If something doesn’t feel right, end the viewing. If individuals become confrontational or refuse to leave, it may be necessary to contact the police. Incidents can also be reported through Action Fraud.
Like many scams, this one relies on catching people off guard. The more widely it’s known, the less effective it becomes.
And when it comes to selling a car, a bit of awareness could make all the difference.
