Can you mix 5W30 and 5W40?

Mixing 5W-30 and 5W-40 motor oils can be done, but it is generally not recommended. Here’s why:

Possible Scenarios When Mixing:

1. If you need to top off your oil and only have a different viscosity available, mixing a small amount of 5W-40 with 5W-30 (or vice versa) is better than running low on oil.
2. If both oils are from the same brand and type (e.g., both synthetic), they are more likely to be compatible.

Potential Downsides:

1. Mixing different viscosities can alter the oil’s performance characteristics, potentially leading to suboptimal engine protection.
2. Using a mixture of oils can void warranties and may not meet the specific recommendations for your engine.
3. Different oils can have varying additive packages, which might not work well together.

Summary:

• For optimal engine performance and protection, use the oil viscosity recommended by your vehicle’s manufacturer.
• If you must mix, do so only in small amounts and as a temporary measure until you can use the correct oil.

In most cases, it’s best to avoid mixing different viscosities to ensure your engine receives the proper protection and performs optimally.

Typical engine oils with the viscosity grades 5W-30 and 5W-40