Can motor oils of different brands be mixed?
1 Answers
Motor oils of different brands can be mixed, but it is not recommended. If it's for emergency purposes, it might be acceptable. It's important to note that when mixing different oils, the viscosity grade and performance level must be the same, for example, both should be fully synthetic 5W30 or fully synthetic 5W40. The potential impacts of mixing different brand motor oils are: 1. Turbidity: Most modern motor oils use sulfonates as dispersants and detergents, while some use salicylates. These two types are not compatible, and mixing them can cause layering, turbidity, and reduced cleaning performance; 2. Abnormal exhaust: Mixing different brand oils may lead to abnormal exhaust smoke, such as black or blue smoke. The mixed oil might become diluted, allowing it to enter the combustion chamber and produce blue smoke, or it might cause poor cylinder sealing, resulting in black smoke; 3. Sludge formation: Mixing different oils can easily lead to sludge formation, which reduces the cooling effect of the lubricant, causing the engine to overheat and potentially leading to malfunctions; 4. Accelerated wear: The anti-wear properties of the mixed oil can change significantly, potentially breaking down the oil film and causing wear between the piston and cylinder wall, or even piston ring breakage in severe cases.
