Does mixing engine oils have an impact on the engine?
2 Answers
There will be an impact. Different types of oils contain different chemical substances, and mixing them may lead to accidents, posing significant safety hazards. It should be avoided as much as possible; otherwise, it will be difficult to accurately assess the quality of the oil. If mixing is necessary under special circumstances, it can be done according to certain mixing principles. Cleaning effect: The cleaning effect refers to removing residues such as carbon and oil produced by combustion, or dissolving these residues in the oil. Through the oil circulation, impurities are carried to the engine oil filter. Engine oil can clean the engine, remove impurities inside the engine, and protect metal surfaces from corrosion by acids formed during combustion. Cooling effect: The cooling effect refers to cooling the engine. Engine oil can assist the cooling system (such as water, radiator, water pump, cooling circulation system, and airflow passing through the engine and oil sump) in removing the heat generated by the pistons. When cooling the pistons, gasoline must be sprayed from the opposite side. Therefore, engine oil must have excellent cooling performance and be able to withstand high temperatures.
Mixing engine oils is absolutely not recommended. I once mixed two different brands out of curiosity, and the car felt sluggish, with unstable RPM and increased fuel consumption. Upon inspection, the oil appeared cloudy with slight sediment. This happens because different oil formulations can conflict, and additives like detergents and anti-rust agents may react chemically, reducing lubrication effectiveness. I learned my lesson and now stick to the same brand and specification, such as full synthetic 5W-30, which restored smooth engine performance. During regular maintenance, I also check the dipstick to ensure no mixing of old oil or new brands. In short, trying to save money with such shortcuts can lead to bigger issues like piston ring wear or carbon buildup, resulting in costlier repairs. It's best not to take this risk.
