Can engine oils from different brands be mixed?

[IsabelleDella]

Engine oils from different brands should not be mixed. Mixing engine oils from different brands can cause chemical reactions, reduce lubrication effectiveness, and produce acidic or alkaline compounds that accelerate corrosion of engine components. The hazards of mixing engine oils from different brands include: 1. Abnormal smoke from the exhaust pipe; 2. Accelerated sludge buildup in the oil; 3. Reduced sealing performance of piston rods or piston rings, leading to discoloration or damage; 4. Increased likelihood of engine malfunctions; 5. Severe wear of pistons and cylinder walls. The functions of engine oil include: 1. Lubrication and friction reduction; 2. Assisting in cooling and temperature reduction; 3. Sealing and leak prevention; 4. Rust and corrosion prevention; 5. Shock absorption and buffering.