Can I mix engine oil viscosity?
Isabella Bartlett
Updated on May 11, 2026
yes you can mix same brand and type oils with different viscosity and it will be fine as long as you don't mix them 50/50. If you mix 200 ml of oil with the rest of oil needed for your engine you will be totally fine.
Is it OK to mix different oil viscosity?
THE ANSWER IS NO!Even if two different brands of oil have the same viscosity, you still should not be mixing them together.
What happens if you mix engine oil viscosity?
Oils are also made available with different grade ratings that determine the viscosity and its ability to perform under varying weather conditions. Can oils of different grades be mixed? The good news is that mixing different types of oil it will not harm your engine in any way in the short run.Can you mix engine oils different weights?
The truth is simple: don't mix two different oils that have different weights (viscosities). Viscosity Grades might sound pretty scientific, but the simple fact is that this is what keeps your engine running smoothly.Can I mix 2 different engine oils?
WHAT ABOUT MIXING ENGINE OIL BRANDS? Yes. It won't harm your engine to mix, for example, Quaker State® motor oil with Pennzoil, as long as the oil you use is the weight (or viscosity) recommended in your vehicle owner's manual.Will Mixing 10 Motor Oils Damage an Engine? Let's find out!
Can you mix 10W30 and 10W40?
Mixing 10W30 with 10W40Some say that mixing them is fine as long as you don't live in freezing weather. Even if you put together synthetic and conventional blends of these motor oils, they show no harm to your vehicle. However, this is true only if you mix in a quart of the other type to your usual engine oil.