Can different engine oils be mixed together?
2 Answers
Engine oils can be mixed together. If the mixing is done strictly following the mixing principles, it will not have much impact on the vehicle. However, mixing different types of engine oils may cause turbidity. Since different brands and types of engine oils contain different chemical additives, these chemicals may react when mixed, reducing lubrication effectiveness and potentially forming acidic or alkaline compounds that can accelerate corrosion of engine components. The principles for mixing engine oils are as follows: 1. The quality of similar products is basically the same, or when high-quality oil is mixed with low-quality oil, it is still considered as low-quality oil. 2. Adjust the physical and chemical properties of the oil, such as viscosity, so that different grades of the same oil can be mixed. 3. Different types of oils can generally be mixed if it is known that neither of the two mixed oils contains additives, or if one does not contain additives, or if both contain additives but do not react with each other. However, after mixing, the quality of the high-quality oil will be reduced. 4. Ordinary mineral oils can be mixed, and mixing is more feasible between mineral oils and semi-synthetic oils. Mixing full synthetic oils with mineral oils should be done with caution. 5. For oils with unknown characteristics and additive compositions, if mixing is indeed necessary, a mixing test should be conducted beforehand to observe whether there are any abnormal phenomena such as strange odors or sedimentation in the mixed oil. If strange odors or sedimentation are detected, the oils should not be mixed. It is advisable to measure the main physical and chemical properties of the lubricating oil before and after mixing.
I've been driving for decades, and mixing engine oil is generally not recommended. Engine oils are formulated with specific recipes, and different brands or types of oil have significant differences in base oils and additive components. Mixing them may cause chemical reactions, such as forming deposits or reducing lubrication effectiveness, which can accelerate engine wear over time and increase maintenance costs. It's best to stick with one brand of oil and choose the correct viscosity grade according to the manual. In case of an emergency where you have no choice but to mix oils—for example, if the oil light comes on while on the road and you can only add a different brand of oil with the same viscosity as a temporary fix—you should go to a professional shop as soon as possible for a complete oil change. Regularly check the condition of the engine oil and maintain a single source to protect the heart of your beloved car.
