Can You Use Diesel Engine Oil In Old Gasoline Powered Cars?

It's easy for the uninitiated to think that oil is oil, no matter what type of engine it's going into. After all, it's only meant to lubricate the internal components of an engine. Well, all oils might conduct the same function, but just like the engines they're going into, they're not all designed equally.

For starters, a diesel engine runs significantly hotter than a gas-powered one; it takes much more heat to ignite diesel, which will burn its oil differently. The chemical makeup of diesel and gasoline engine oil is designed to meet the demands of its respective engines. While they come with many of the same additives, such as zinc, anti-foam, and detergent, the volume of those additives varies in quantity because each engine requires different levels to function properly.

Containing too much of one additive and not enough of another can negatively impact an engine. You shouldn't pour diesel oil into your gasoline-powered engine because certain ingredients could cause irreversible damage.

Diesel engine oils contain significantly more zinc dialkyldithiophosphate (ZDDP) than basic passenger motor oil. ZDDP is a powerful anti-wear and anti-oxidant solution added to motor oil to ensure optimal performance. However, the different speeds between diesel and gasoline-powered engines activate ZDDP at different rates, requiring very specific levels of ZDDP in the oil.

Additionally, diesel oil and gas-powered oil come with varying amounts of anti-foam additives. The motion of components in the drivetrain and powertrain leads to a buildup of foam that can have harmful ramifications for the engine. To combat this, anti-foam additives are blended into the oil, and the number of additives in each kind of oil is different. Oil designed for a high rpm engine will have twice as many anti-foam additives in it than a diesel formula.

Lastly, diesel oil contains significantly more detergent than gasoline engine oil. Detergent additives in oil not only help keep metal components clean, but also neutralize acids. The amount of detergent in diesel oil will remove factory-applied coatings on the internal components, leading to more oil in the exhaust. This will ultimately damage the catalytic converter, that thing that California is trying to stop people from stealing. Do not put diesel engine oil into your gasoline-powered engine if you value your vehicle and don't want an expensive repair bill.