Can motor oils of the same brand be mixed?
4 Answers
When topping up motor oil, it is recommended to use the same brand and type of oil. If the oils are from the same brand but different types, they can be mixed, but it is not advisable for long-term use. The reasons are as follows: 1. It alters the oil composition: Motor oil is primarily composed of base oil and additives, and different types of oil are not identical. Mixing two different types of oil, while maintaining the lubrication properties, will inevitably change the oil composition. 2. It may affect the engine: The altered oil composition could have adverse effects on the engine, hence long-term use of mixed oils from the same brand but different types is not recommended.
I once mixed motor oils of the same brand, and the consequences weren’t great. That time, I was low on oil and casually poured another bottle of 5W-30 into the engine, which originally had 0W-40 of the same brand. After a few days of driving, the engine started making strange noises and had jerky acceleration. A friend reminded me that even within the same brand, different viscosities can cause the base oils to react, and additive conflicts may lead to insufficient lubrication. After getting the car repaired, I learned that mixing oils like this can accelerate component wear and even shorten the oil’s lifespan. Now, I only replace the oil entirely during oil changes to avoid small mistakes leading to major losses. Remember to check the oil specifications for consistency—mixing small amounts of the same type in an emergency might be acceptable, but long-term mixing is definitely not advisable. Motor oil is the engine’s protective shield—don’t cut corners and end up harming yourself. Develop a habit of regular maintenance; the money spent is worth it.
Mixing engine oils carries significant risks, which I've researched extensively. Even within the same brand like Shell or Mobil, their extensive product lines (such as mineral oils versus full synthetics) use different additive packages that can chemically react when mixed, compromising viscosity stability. Modern precision engines are particularly vulnerable - blending different formulations reduces anti-wear performance. Through garage testing, I've observed mixed oils tend to foam or form sediments, accelerating degradation. While emergency short-term mixing of similar viscosity products from the same brand may work temporarily, complete oil changes should follow promptly. Always consult your owner's manual - manufacturers uniformly advise against mixing. The smarter approach? Purchase full containers for complete changes, ensuring your vehicle maintains like-new longevity.
Don't mix engine oils, that's my experience. Even within the same brand, the differences can be huge. When viscosities don't match, the engine goes haywire—increased noise, faster wear. I once saw a friend mix oils, and the car's warning light came on. The mechanic said it could easily lead to lubrication failure, and it's best to change the oil completely. Adding a small amount of the same oil is fine, but avoid mixing long-term. Safety first, regular maintenance means fewer headaches.
