Can A Motorcycle Use Car Engine Oil? – (Mechanic Thoughts)

Engine oil is an essential lubricant for all automobiles. The main purpose of engine oil is to lubricate an engine’s various moving parts. Lubrication reduces the friction and wear and tear of components and prevents corrosion.

It also helps in keeping the engine parts cool. Changing the engine oil to improve the engine performance regularly is recommended.

If you’re a motorcyclist and DIYer like me, I’m sure you’ve changed your motorcycle engine oil many times. Many people think – all motor oil is the same and one can be replaced with another, but that’s not true.

So, can a motorcycle use car engine oil? No, you should never put car engine oil into your motorcycle because the viscosity and additives of motorcycle engine oil differ from cars. A motorcycle uses a wet clutch system, which requires balanced frictional characteristics for power transfer to the drivetrain.

Is Car Engine Oil the Same As Bike?

The frictional characteristic of motorcycle engine oil is different from cars. In cars, the engine and clutch plate are available at different places, while the motorcycle shares the same cabinet. Also, the car has a dry clutch plate, but the motorcycle uses a wet clutch system for power transmission.

So, the same oil lubricates the engine piston and clutch plates in the motorcycles. Hence, a balanced frictional characteristic is required for motorcycle engine oil.

If you use car engine oil in a motorcycle, power loss may occur from the clutch system to the drivetrain, giving your motorcycle lower MPG. (I have written a detailed guide on motorcycle MPG, you can read that)

That’s why it’s not recommended to use car engine oil to lubricate the motorcycle engine. You should only use your manufacturer’s specified engine oil in your motorcycle.

What Is The Difference Between Motorcycle Oil And Motor Oil?

The oil sump size of the motorcycle is much smaller than that of cars and trucks. So, it contains lesser oil to cool down the moving parts and engine.

Generally, the oil sump capacity of a motorcycle is 3 to 5 liters, while in cars and trucks, the sump capacity is 8 to 16 liters.

It means motorcycle engine oil should have a higher heat dissipation rate to keep the engine cool and protect it from wear and tear. Hence, it should have higher heat conduction properties for fast dissipation.

Also, the same engine oil lubricates the clutch system and gearbox, which means it should have a balanced frictional characteristic that prevents power loss.

While that’s not the case with motor oil used in cars and trucks. Because cars and trucks have higher sump capacity, and it has separate gearbox and clutch system that doesn’t require lubrication.

Also, the viscosity of motorcycle engine oil is different from motor oil used in cars and trucks because it should be formulated to travel smoothly through narrower pathways and protect the moving parts from oxidation and corrosion.

What Will Happen If You Use Car Engine Oil in Motorcycle?

The viscosity and frictional characteristics of motorcycle engine oil are balanced so that it won’t cause power loss.

At the same time, car engine oils contain friction modifiers, which could lead to slipping and power loss on acceleration.

Also, modern car engine oils require less viscosity. So, using low-viscosity oil in your motorcycle may not protect your geartrain and other moving components from wear and tear, which could lead to engine failure.

Will Car Oil Ruin Your Motorcycle Engine?

If you’re thinking of top-up your motorcycle with your car engine oil, then don’t make this mistake! Using car oil on your motorcycle may ruin your motorcycle gearbox and clutch system because your motorcycle shares the same oil for engine lubrication and clutch plates.

Conclusion

The frictional characteristics and viscosity of motorcycle engine oil differ from motor oil. That’s why companies like Valvoline and Castrol sells separate oil for car and motorcycle. You should never replace your motorcycle engine oil with general motor oil because it can ruin your gearbox and clutch plates.