'That's All They Had': Mechanic Shocked By What Comes Out of Customer’s Oil Pan. Then He Finds Out What They Put In

"Forbidden."

Mechanic Can’t Believe What Came Out of Customer’s Oil Pan. Then He Finds Out What They Put In

Photo by: Mike Lorusso & Just Rolled IN

Stacy Fernandez

By: Stacy Fernandez

Nov 22, 2025 at 6:00pm ET

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Not all oil is created equal. There’s a reason some are found at a car shop while others are in your local grocery aisle.

And no, they’re not interchangeable—that’s a lesson one car owner learned in what may end up being an expensive and avoidable mistake.

The result of putting the completely wrong category of oil will surprise you.

Why Does This Oil Look Like Laffy Taffy?

In a viral Facebook video, content creator Just Rolled In (who reposts car content submitted by others) shares how using the wrong type of oil in your vehicle can wreak absolute havoc.

In the video, you can see that what is supposed to be motor oil has transformed into a thick black goop. Even when the mechanics try to pour the semi-solid gunk out, it’s so thick that it moves slowly like molasses trying to defy gravity.

The narrator explains that the vehicle's owner called mobile mechanics to inspect the car.

"The customer said their car was low on engine oil, so they added five liters of cooking oil as that's all they had," the narrator says.

The black gunk was allegedly the result of the two oil types mixing together. According to the video, they were able to clean up the mess by flushing the engine a few times.

Can You Use Cooking Oil in Your Car?

Some people have wondered if cooking oil could work as an emergency substitute for motor oil. Experts say absolutely not.

"Cooking oil does not work in an engine," Claude Townsend, program coordinator and master instructor in automotive service at Oakland Community College, told USA Today.

He said manufacturers spend significant time ensuring fluids meet a vehicle's specific design needs, and cooking oil simply isn't equivalent to engine oil, even though they both lubricate.

What Drivers Are Saying

‘That’s Where I Draw the Line’: Mechanic Starts Working On Car. This Is the Moment He Realizes He Bit Off More Than He Can Chew

'What the [Expletive] Is That?:' Customer Complains Car is 'Shaking Like Crazy.' Then His Mechanic Takes a Closer Look At The Tire

Cooking oil is too thick and sticky to flow through an engine properly, and it can't handle the extreme temperatures motor oil has to withstand.

HowStuffWorks explains that pouring vegetable oil into your engine will ruin it. The oil burns and becomes a sticky, gummy mess that solidifies and builds up, causing the engine to seize up, burn out, or stall.

It can result in engine seizure, stuck pistons, broken crankshafts, damaged camshafts, and worn-out bearings.

Using cooking oil as fuel in diesel engines is a totally different thing. Some older diesel vehicles with mechanical injection systems can technically run on vegetable oil, but only with modifications that allow for its use. You'd need a second fuel tank for the oil, plus extras like a heating system to reduce viscosity and new fuel injector nozzles.

The engine must start on regular diesel, switch to vegetable oil once warmed up, and then switch back to diesel before shutting off, so that no oil remains in the fuel lines.

Even then, it's not exactly legal everywhere. In the US, you need special licenses and have to pay motor fuel taxes. Additionally, vegetable oil isn't considered a reliable fuel source for long-term use, as it can still clog fuel lines and necessitate shorter oil change intervals and increased engine maintenance.

People who commented on Just Rolled In’s post were amused and horrified alike.

"Did it ‘fry’ the bearings," a top comment reads.

"Dude turned his engine into a taffy puller," a second said.

"That's not oil that's flubber," another wrote

What do you think?

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Comments

"What did they flush it with? DAWN?!" a fourth added.

Motor1 reached out to Just Rolled In via Instagram and Facebook direct message. We’ll update this article if they respond.