can you use motorcycle engine oil in a car

[StNorah]

No, you should not use motorcycle engine oil in a car. While the base oil might be similar, the additive packages are formulated for fundamentally different engine designs and operational requirements. Using motorcycle oil in a car can lead to inadequate engine protection, potential damage to the catalytic converter, and compromised performance.

The primary difference lies in the additives. Car engines have a separate lubrication system, so their oil contains additives to control soot and acidity. Motorcycle engines often share oil between the engine, clutch, and transmission. Therefore, motorcycle oil must be formulated to be "wet clutch compatible," meaning it lacks the friction-modifying additives common in car oils. Using car oil in a motorcycle can cause the clutch to slip, but the reverse—using motorcycle oil in a car—introduces a different set of problems.

A critical risk involves your car's emissions system. Many modern motorcycle oils still contain high levels of phosphorus and zinc (ZDDP), which are excellent for protecting high-revving, flat-tappet motorcycle engines. However, these elements can poison and destroy the sensitive catalytic converter in your car, leading to a very expensive repair. Furthermore, the oil may not meet the specific API (American Petroleum Institute) service categories required by your car's manufacturer, such as SN, SP, or the newer GF-6 standards for fuel economy and engine protection.

Feature	Car Engine Oil	Motorcycle Engine Oil (Wet Clutch)	Risk of Using Motorcycle Oil in Car
Friction Modifiers	Often contains them to improve fuel economy	Lacks them to prevent clutch slippage	Can lead to reduced fuel economy
Detergent/Dispersant Package	Formulated for high soot control (from EGR)	Less robust soot handling	Potential for increased engine sludge
Phosphorus (ZDDP) Content	Strictly limited to protect catalytic converters	Often higher for valvetrain protection	Can damage/destroy the catalytic converter
API Certification	Meets specific categories like API SP	May not meet any auto-specific API standards	Engine warranty may be voided; inadequate protection

Stick with an oil that carries the correct API "donut" and viscosity grade recommended in your car's owner's manual. It's a simple step that ensures proper lubrication, longevity, and protects your investment.

[MaggieDella]

As a mechanic, I've seen this tried. It's a bad idea. Your car's oil has to handle soot from the EGR system and protect the catalytic converter. Motorcycle oil isn't built for that. It might seem fine for a short while, but you're risking long-term damage to your emissions system and not getting the right protection for your engine bearings. It's just not worth the risk to save a few bucks on an oil change.

[LaAmy]

Think of it like this: motorcycle oil is a specialized tool for a job that includes lubricating a wet clutch. Your car's engine doesn't have that job. Using the wrong oil is like using a screwdriver to hammer a nail—it might work in a pinch, but you'll likely damage both the nail and the screwdriver. Always use the tool, or in this case, the oil, designed specifically for the task.