The Benefits and Drawbacks of Mixing Synthetic and Regular Motor Oil

Is it wise to mix synthetic and regular motor oils in your engine? The answer is often no, with a few exceptions. This article explores the benefits and drawbacks of such a mix, helping you make an informed decision.

What Are the Benefits of Mixing Synthetic and Regular Oil?

There are very limited benefits when mixing synthetic and regular motor oil, and the drawbacks can be significant. Some argue that a small amount of synthetic oil mixed with regular oil can provide some additional protection. However, the reality is that the protection level will still be at the level of the regular oil, especially if you have a relatively high volume of regular oil in the system.

Blended off-the-shelf oil products may use selected crude oil grades and blending agents to improve the quality of the oil. But they do not offer the full range of benefits that pure synthetic oil does. Mixing synthetic and regular oil is not recommended unless you are topping up a low oil level and don't have enough synthetic oil to satisfy the entire system.

Common Scenarios for Mixing Oil

If your oil level is low, and all you have is a quart of synthetic oil, then it might be worthwhile to add it. While it won't hurt your engine, it's better to have the synthetic oil at a minimum than to risk damaging your engine due to insufficient lubrication.

The Drawbacks of Mixing Synthetic and Regular Oil

Mixing synthetic and regular oil is generally discouraged, especially in vehicles that require synthetic oil. The primary reason is that synthetic oil provides better performance and engine protection. Mixing synthetic oil with a large volume of regular oil can dilute the effectiveness of the synthetic oil, which is why it is not recommended.

Using Conventional Oil with Better Synthetic Options

Using conventional oil when synthetic oil is available is generally not recommended. Synthetic oil offers superior protection, and using a blend of both can diminish the benefits of the synthetic oil. Manufacturers typically do not mix multiple types of synthetic oil in their formulations for a reason.

Choosing Between Synthetic, Blended, and Conventional Oils

For those who want to be cost-conscious, synthetic blend oils offer a good balance. They are less expensive than fully synthetic oils but more expensive than conventional mineral oils. Synthetic blends are a popular choice among car owners who want a compromise between cost and performance.

Many dealerships, like those servicing Ford vehicles, use synthetic blends as a default option unless specified otherwise. These oils are designed to keep your engine running smoothly and maintain good performance between oil changes.

Can Mixed Oil Be Blended in the Car?

Technically, you can blend synthetic and regular oils, but it is not the best practice. Different grades and weights of oils can be mixed, creating a 50-50 blend, but this is not recommended. Synthetic, semi-synthetic, and mineral oils are miscible with each other, meaning they can be mixed. However, it's best to stick to a single type of oil to ensure optimal engine performance.

Conclusion

While there is a very minimal benefit to mixing synthetic and regular motor oils, the drawbacks outweigh the benefits. Unless you are topping up a low oil level and have limited synthetic oil, it is generally best to use the recommended type of oil for your vehicle. Synthetic oils offer better protection and longevity, making them the optimal choice for those who want to keep their engines in top condition.