How to Spot the Oil in the Engine Scam When You Sell a Car
Every fact, figure and legal citation in this article was checked against its original source before publication by Artūras Andriušaitis, founder and editor. Editorial Standards
The oil in the engine scam turns a buyer’s inspection into sabotage. While one “buyer” keeps you talking, another pours oil where a hot engine will make it smoke, and after the test drive the group tells you the engine is finished and offers cash for what is left. Sheriffs and police in four states have warned sellers about it or announced arrests since January 2024; anyone charged is presumed innocent unless proven guilty. The scam needs two things from you: a minute in which nobody watches your car, and a sale on the spot. You can refuse both.
How the oil in the engine scam works
A buyer answers your listing on Facebook Marketplace or Craigslist and often arrives with two or three others posing as friends or mechanics, the San Luis Obispo County Sheriff’s Office warned in March 2025. One of them keeps you busy while another goes to the car. A seller in San Diego County told FOX 5 that one person distracted him by counting money and asking for the title while another poured oil into the coolant reservoir. The whole con took less than a minute and cost him $500 in repairs.
The reports differ on where the oil goes: on the engine, into the radiator or the coolant reservoir, or into the tailpipe. In a notice in February 2024, the Placer County Sheriff’s Office described a suspect pouring oil into the radiator and on top of the engine, and another pouring oil near the rear of the car. Once the engine warms up on the test drive, the oil smokes, and the suspect points to the oil in the radiator as proof that the engine is “blown.” Then comes the offer. “Some vehicles that were listed for $10,000 were sold for as little as $500,” Detective Edward Welter of the Grays Harbor County Sheriff’s Office told KIRO 7.
The car does not stay with the crew. The Placer County Sheriff’s Office says the three men it arrested in May 2026 resold the cars at full value. KIRO 7 reported that cars taken this way are considered stolen by fraud, and Lieutenant Krusey of the Puget Sound Auto Theft Task Force warned that the next buyer can end up “out the money and the vehicle as well.” In September, FOX40 reported that the Placer County office had returned $12,000 to a family that had unknowingly bought a stolen vehicle from the three men.
In Minnesota, the five suspects whose arrests the Hennepin County Sheriff’s Office announced in August 2025 allegedly rolled back the odometers and resold the cars for double the price, KSTP reported. For buyers, it is one more reason to know the physical signs of a rollback.
Where police have warned about it since 2024
No agency we found keeps a national count of the oil in the engine scam, so we counted what agencies announced. We searched sheriff’s and police websites, the Justice Department’s press releases and news reports that carry an agency’s statement for every official US warning and arrest from 1 January 2024 to 22 October 2026. We found 15 announcements from agencies in four states: nine warnings and six arrests, ten of them in California. The crews travel, though. Placer County detectives traced the crew they arrested in May 2026 through at least eight counties, and KOAM’s report on the Barry County warning in Missouri says two cars connected to the scam were recovered in Irving, Texas.
This is a count of what agencies announced, not of scams. La Mesa police say victims are often too embarrassed to come forward, and a Missouri seller who did report was told by the sheriff’s office that it was a civil matter because he had agreed to the sale, KY3 reported. A state with no warning on the map is not a state without the scam.
The table lists each announcement with its source, and the 2026 rows are also in our Used Car Scam Log, which adds the official warnings and enforcement actions on used car scams each month. By 22 October 2026 we had found one outcome: the three men the Placer County Sheriff’s Office arrested in May 2026 have pleaded guilty to crimes including elder fraud, according to the FOX40 report. We found no report of a plea or a verdict in the other cases.
| Announced | Agency | What it announced | Source |
|---|---|---|---|
| Jan 2024 | Nevada County Sheriff’s Office, California | Warning. Several sellers reported buyers who looked under the hood, claimed a mechanical problem and offered a much lower cash price. | Sheriff’s notice |
| Feb 2024 | Placer County Sheriff’s Office, California | Warning. Oil poured into the radiator and on the engine; cases in Placer, Nevada, El Dorado and Sacramento counties. | Sierra Sun Times |
| Jul 2024 | Greene County Sheriff’s Office, Missouri | Warning. A deputy’s advice to sellers, in a report on a seller near Ozark who asked $4,300 and settled for $1,300. | KY3 |
| Sep 2024 | Redding Police Department, California | Warning. Its first reported case; police say the oil goes into the radiator, on the engine and into the exhaust pipe. | KRCR |
| Sep 2024 | Placer County Sheriff’s Office, California | Arrest. One of three men charged with felony vandalism and theft by false pretense was arrested in Oklahoma in July; two were still wanted. | Sierra Sun Times |
| Nov 2024 | Bear Valley Police Department, California | Warning. Two buyers claiming to be father and son; investigators believe they may pour oil on the engine, which appears to leak oil after the test drive. | Police notice |
| Jan 2025 | La Mesa Police Department, California | Warning. Two reports received; sell at the transaction zones in front of the station. | FOX 5 San Diego |
| Mar 2025 | San Luis Obispo County Sheriff’s Office, California | Warning. Sellers in Atascadero and Los Osos accepted offers far below their asking prices. | Sheriff’s release |
| May 2025 | San Luis Obispo County Sheriff’s Office, California | Arrest. Two arrested at a traffic stop in April; more than 20 reported incidents in the county from November 2024 to March 2025, with an estimated $60,000 lost. | Sheriff’s release |
| Aug 2025 | Hennepin County Sheriff’s Office, Minnesota | Arrest. Five arrested in Minneapolis; investigators believe at least a dozen people lost tens of thousands of dollars. | KSTP |
| Oct 2025 | Placer County Sheriff’s Office, California | Arrest. Two arrested in Newcastle at a second meeting arranged after the seller called deputies. | Mountain Messenger |
| 2025 | Barry County Sheriff’s Office, Missouri | Warning. Oil poured into the radiator overflow tank; two vehicles tied to the scam recovered in Irving, Texas. | KOAM |
| Apr 2026 | Grays Harbor County Sheriff’s Office, Washington | Arrest. Three arrested; $57,000 in cash and more than 20 car titles seized. | KIRO 7 |
| May 2026 | Placer County Sheriff’s Office, California | Arrest. Three arrested after a traffic stop near Red Bluff; detectives traced the crew through at least eight counties. | Sheriff’s release |
| May 2026 | Puget Sound Auto Theft Task Force and Grays Harbor County Sheriff’s Office, Washington | Warning. At least 26 victims identified in the region. | KIRO 7 |
How to sell your car without giving them the chance
The advice repeats from one sheriff’s notice to the next, and each rule closes one of the gaps the crews use.
- Never leave a buyer alone with your car, and that includes the test drive. The Nevada County and San Luis Obispo County sheriffs’ notices both make this point.
- Bring someone with you. “If you have two sets of eyes, you’re not going to be distracted,” Lieutenant Krusey told KIRO 7. The crews split up: Placer County’s notice describes one suspect at the engine while the others ask to look in the trunk or keep the seller busy, and another pouring oil near the rear of the car.
- Ask for the buyer’s ID. Bear Valley police in California advise sellers to request identification and say a refusal may indicate fraudulent intent.
- Meet in public, at a police exchange spot if there is one near you. La Mesa police point sellers to the transaction zones in front of their station, Placer County deputies say the parking lot of any of their offices can be used, and the Placer County release of May 2026 suggests a DMV office. A careful buyer may still ask to see the car at your home, because a seller who will not meet at home is one sign of a curbstoner; if you agree, keep the other rules.
- Have a mechanic check the car before you list it. “If you’re selling your vehicle, it never hurts to bring it to a reputable mechanic beforehand to get fully checked out,” a Hennepin County detective told KSTP, and a seller who has just had the car checked knows that a sudden engine failure is not true.
If your car starts smoking during the visit
Do not cut the price on the spot. The Nevada County and San Luis Obispo County notices say not to give in to pressure to drastically reduce the price until a trusted mechanic has inspected the car. “If your car wasn’t broken when you showed up, it probably isn’t broken when you’re leaving,” Detective Welter told KIRO 7. The Placer County Sheriff’s Office put it more simply in May 2026: “If something feels off, it probably is.”
End the meeting and call the police or the sheriff where it happened, even if you already sold. Calls from sellers have led to arrests. In Newcastle, California, a seller who suspected tampering told the buyers to come back another day and called deputies, who arrested two men at the second meeting, according to the Mountain Messenger. In Grays Harbor County, Washington, a seller who realized it was a scam called the sheriff’s office, and authorities tracked a suspect’s license plate to an address in Renton; three people were arrested, KIRO 7 reported.
The smoking engine is not the only trick aimed at private sellers. Fake cashier’s checks and payments that are later reversed are covered in the sellers’ section of our overview of car scams to look out for, and more of the scams we track are in Scams & Fraud.
The Bottom Line
The oil in the engine scam works only when a seller leaves the car unwatched for a minute and then agrees to sell on the spot. Meet in public, bring someone, stay with whoever is at your car and have a mechanic check it before you list it. If smoke appears during the visit, end the meeting, have your own mechanic look at the car and report it to the police. A car that drove fine to the meeting probably did not break during it.
