Mechanic Works On New Hyundai Elantra. Then He Realizes It Has Too Much Break-In Oil: ‘All Of Them Do This’

A mechanic working on a 2025 Hyundai Elantra with around 2,500 miles on it spotted something strange with its oil.

The service tech, who posts under the handle Mr. Crowley (@jcrowley6) online, said he’s noticed the same issue on other Hyundais. Prompting the question: is there something going on with Hyundai’s break-in oil?

In his video, Crowley says, “I feel like the general public will just figure this to be pretty interesting.” The car’s oil filter has brown-colored oil resting at the bottom.

The tech calls the mass of liquid a troubling sight, considering the vehicle’s low mileage. “This car is a ‘25 Elantra? And it’s got less than 2,800 miles on it, it’s got 2,608 miles on it. You see all that in there? That’s a, yeah, from factory, these cars do this. Same thing with the Palisade. Same thing with the Santa Fes, all of them do this,” he says.

In the comments section, Crowley wrote that he’s “cut open filter of 5k mile Chevy 5.3s and 6.2s and they weren’t contaminated at all.” Others who commented countered that it is actually common in other brands.

What Is Break-In Oil?

When an engine rolls off the assembly line or it’s been rebuilt, it's essential to use break-in oil. This short-term lubricant possesses restrictive friction properties that allow for vital internal components to set properly inside the engine. Traditional oil is relatively frictionless in comparison. If traditional oil is poured into an engine immediately without using break-in oil first, parts like piston rings can’t set properly.

The chemical makeup of break-in oil also differs in that it contains increased amounts of ZDDP (Zinc Dialkyldithiophosphate). As it travels through the engine block, hot temperatures help create a film that clings to an engine’s internal metallic surfaces. This assists in preventing any harsh metal-on-metal contact. However, long-term usage of break-in oil is not recommended — it’s formulated just for the initial break-in of a car engine. Afterwards, you should use standard motor oil.

As Driven Racing Oil explains, “Break-in oils have high levels of zinc and phosphorus (ZDDP) to protect flat-tappet camshafts and other high-wear areas during the initial run-in. Standard modern oils often lack these additives because they can harm catalytic converters over long periods, but for the break-in, that extra protection is non-negotiable."

VP Racing Fuels calls this oil “a critical component of an engine rebuild [as] it allows controlled friction in low-load areas like piston rings.” It adds that using synthetic motor oil at the beginning of an engine’s life cycle is a bad idea as they can “actually prolong break-in time. They also have potential to glaze cylinders, which will incapacitate proper ring seating."

Is There Something Wrong With The Hyundai Elantra’s Filter?

Other folks have uploaded pictures of their own break-in oil changes. A Reddit user’s break-in oil change that was completed at the 1,550 mile mark shows a bit of break-in fluid at the bottom of the filter. However, they noted that there are tiny bits of metal shimmering in the oil. This indicates that some of the engine’s internal components were shaved off due to the break-in oil’s controlled level of friction. This suggests that the break-in oil was doing its job.

Furthermore, a CarParts.com technical guide says that “finding metal shavings in oil is normal because engine parts naturally wear down.” It’s the job of oil filters to filter out these contaminants over time.

Judging from the 2021-2026 Hyundai Oil Filter Housing & Maintenance Standards description guide on Hyundai OEM Parts Online, there’s nothing to suggest the brand uses filters that differ from other auto manufacturers.

Filtron’s technical guide on filter housing check mechanisms provides an explanation that may be why there was break-in oil pooling at the bottom of the 2025 Elantra’s filter. The auto parts manufacturer says “the purpose of the anti-drainback valve is to prevent … oil from escaping from the filter when the engine is switched off," i.e., the break-in oil pooling at the bottom of the filter showed in Crowley’s video is likely trapped as a means of helping to prevent dry friction of an engine’s inner metallic components.

Motor1 has reached out to Crowley via TikTok direct message for further comment. We'll update this if he responds.