You buy a used car, drive it for a week or two, and then—check engine light. Overheating. Strange noises. Now you’re wondering: did the seller know about this problem, or did you just get unlucky?
The difference between fraud and normal wear-and-tear isn’t just about who’s to blame—it decides whether you can do anything about it.
Engine repairs run expensive, often $5,000 to $15,000 for major work. Some problems genuinely come out of nowhere. Others happen because a seller knew the engine was failing and hid it long enough to close the deal.
What Counts as Fraud
For fraud to exist in a car sale, there has to be more than just a broken engine. The seller needed to know about a serious problem beforehand.
They had to hide it or lie about it. You relied on what they told you (or didn’t tell you) when deciding to buy. And you got hurt financially because of it.
Here’s what fraud often looks like with engines:
- Rolling back the odometer to hide wear on a high-mileage engine
- Covering up mechanical failures with quick fixes or additives that only work temporarily
- Adding thick oil or stop-leak products right before you test-drive the car
- Faking maintenance records or claiming the car was serviced when it wasn’t
- Hiding previous engine repairs or swapping in a used engine without disclosure
- Not mentioning flood damage that affects the engine
The critical piece is intent. The seller had to know there was a problem and deliberately keep you from finding out.
What’s Normal for a Used Car
Used cars have miles on them. Things wear out. Certain engine issues fall within what you should expect when buying something that’s not brand new.
Older cars develop problems over time. Gaskets crack. Hoses get brittle. Oil consumption increases gradually. This is what happens to engines as they age.
What’s “reasonable” depends heavily on the car’s age, mileage, and price. A ten-year-old car with 150,000 miles will have more wear than a three-year-old with 30,000 miles. Buyers pay less for high-mileage vehicles because they understand there will be more maintenance.
Normal wear assumes proper maintenance happened. If someone changed the oil on schedule and did recommended service, gradual wear is expected and usually not the seller’s problem after the sale.
Red Flags That Point to Concealment
Some patterns strongly suggest the seller knew about problems and worked to hide them.
Fresh oil right before sale
Sounds like good maintenance, right? Sometimes. But sellers also change oil immediately before selling to hide metal shavings, coolant mixing with oil, or other signs of damage. When you or a mechanic check the oil, it looks clean—because it is. The contamination that would have told the story is gone.
Recent engine additives or stop-leak products
These temporarily mask symptoms. They quiet noisy valves, reduce oil consumption, or slow leaks. They don’t fix anything. If you find evidence of these products shortly after purchase, the seller was managing a failing engine long enough to sell it.
Vague answers about maintenance
Honest sellers usually have service records or straightforward answers. When someone says “I don’t really remember” or “I just changed it when the light came on,” they might be dodging questions about documented problems.
Disconnected warning lights or cleared diagnostic codes
If a check engine light was on but the seller cleared the code without fixing what caused it, they hid a known problem. Dealerships that falsify information engage in fraud even when they try to cover their tracks with paperwork.
Strange title activity
Quick transfers between related parties or suspiciously fast flips can mean someone’s trying to distance the current seller from known defects.
Timeline Matters
When problems show up matters a lot.
Problems within days or weeks of purchase—especially catastrophic ones like seized engines or blown head gaskets—usually existed before the sale.
Major engine failures rarely happen without warning signs. If your engine fails in the first month, odds are the seller knew something was wrong.
Issues that develop gradually over months and thousands of miles more likely represent deferred maintenance catching up or normal aging.
A small oil leak six months after purchase probably isn’t fraud.
But timeline isn’t everything. An immediate problem in a 20-year-old car with 200,000 miles might still be wear-and-tear.
And a problem appearing months later could still be fraud if evidence shows temporary fixes were used to hide it.
Pre-Purchase Inspections and Disclosure Requirements
California law requires licensed dealers to disclose certain significant issues: flood damage, lemon law buybacks, salvage titles, and material frame damage.
However, dealers aren’t required to disclose every mechanical problem. What they can’t do is lie when asked directly, or actively conceal known defects.
Private party sellers have fewer formal requirements, but fraud is still fraud. If you ask a private seller about the engine and they lie, that’s actionable.
Pre-purchase inspections create important evidence. If a mechanic inspected the car before you bought it and found nothing wrong, but major problems appeared right after, that timeline suggests active concealment.
On the flip side, if an inspection found engine concerns and you bought anyway, you probably assumed that risk.
Get a Diagnostic Report Immediately
When engine problems show up, take the car to an independent certified mechanic right away. Ask for a detailed written report that explains the problem, what likely caused it, and approximately when it started developing.
Good mechanics can often tell whether a problem existed before your purchase.
Coolant leaking into cylinders leaves specific deposits that indicate long-term issues. Metal shavings in oil point to bearing wear that developed over time. Carbon buildup patterns reveal maintenance history.
Ask your mechanic specifically: would this problem have been detectable before I bought the car?
Ask for their professional opinion on whether it developed suddenly or had been ongoing. Their testimony becomes powerful evidence if you take legal action.
Save everything—diagnostic reports, repair estimates, correspondence. Photograph contaminated fluids, damaged parts, warning lights. Build your case while the evidence is fresh.
Dealers vs. Private Sellers: Different Standards
Your protections differ dramatically depending on who sold you the car.
Licensed dealers operate under strict regulations. California’s implied warranty of merchantability means vehicles sold by dealers must be reasonably fit for normal use. This warranty typically lasts 30 days or 1,000 miles for used cars, though it can extend up to 90 days depending on the express warranty provided at sale.
Importantly, dealers who sell “as-is” still can’t commit fraud. The “as-is” disclaimer doesn’t protect dealers who actively hid known problems or made false statements.
Private sellers don’t carry the same implied warranties, but they still can’t commit fraud. If a private seller tells you “the engine runs great” while knowing it burns oil and overheats, that’s fraud regardless of it being a private sale.
Manufacturer Defects: A Different Issue
Sometimes engine problems stem from manufacturing defects rather than seller fraud. Certain models have known engine issues affecting entire production years.
If your problem matches a known manufacturer defect, you may have claims against the automaker in addition to (or instead of) the seller.
Research whether your vehicle has Technical Service Bulletins or class action lawsuits related to engine problems.
Manufacturing defects within the warranty period may qualify for lemon law protection, regardless of whether the seller knew about them.
What to Do If You Suspect Fraud
Act quickly. California has a three-year statute of limitations for fraud claims under the Consumer Legal Remedies Act, but the clock starts when you discover the fraud. Waiting costs you evidence and leverage.
Gather everything: advertisements, text messages, emails, and any statements about the vehicle’s condition
. Get that diagnostic report establishing both the problem and when it likely began.
Contact the seller in writing. Explain the problem and request a solution. Keep copies of everything. Their response—or silence—becomes evidence.
Sellers who won’t respond or get defensive often knew about problems beforehand.
Your Legal Options
When fraud is proven, several remedies become available. Rescission lets you unwind the entire sale—you return the car and get your money back, plus certain expenses.
Alternatively, you can seek damages covering repair costs, the difference between what you paid and what the car was actually worth, and potentially punitive damages if the fraud was egregious.
California law provides for attorney fees in many consumer fraud cases, meaning you can often pursue claims without paying upfront legal costs.
Get Help From Experienced Consumer Protection Attorneys
The attorneys at Consumer Action Law Group know how to investigate used car fraud cases involving engine problems. We understand how to determine whether problems were concealed, gather evidence that holds up, and hold dishonest sellers accountable.
If you’ve discovered significant engine problems shortly after buying a used car and suspect the seller knew but didn’t disclose them, contact us today for a free consultation.
We handle cases on a contingency basis—you pay nothing unless we successfully recover compensation on your behalf.
Don’t let fraudulent sellers cost you thousands of dollars. Call us at (818) 254-8413 or visit lawyersforconsumers.com to learn more about your rights.
