When you delve into online auto repair forums, especially those buzzing with discussions around engine maintenance and oil changes, you might stumble upon countless threads debating the best practices for engine care. One question that frequently surfaces, often sparking heated discussions, revolves around engine oil – specifically, whether it’s ever a good idea to mix different types or brands of oil. While the spirit of experimentation and DIY is alive and well in these communities, when it comes to something as critical as engine lubrication, caution is paramount.
The core function of engine oil extends far beyond simple lubrication. It’s a complex fluid engineered to clean engine components, dissipate heat, reduce friction between moving parts, and even enhance fuel efficiency. To achieve these multifaceted roles, oil formulations are meticulously crafted, often using different base oils such as Polyalphaolefins (POA), esters, and mineral oils. Furthermore, various brands and even different grades within the same brand incorporate unique additive packages designed to optimize performance for specific conditions, such as “Low Sludge” formulations or those that “Fight Thermal Breakdown.”
Consider this scenario: you’re topping off your engine oil and have some 0w20 “Low Sludge” oil and some 0w40 “Fights Thermal Breakdown” oil available. Mixing them might seem like a convenient solution, but it introduces uncertainty. What is the resulting grade and, more importantly, what are the combined properties of this mixture? The answer is unclear, and this ambiguity can be detrimental to your engine’s health.
Different oil manufacturers utilize distinct base oils and protective additives. Even within the same brand, formulations vary significantly between grades, catering to diverse needs like heavy-duty performance, daily driving, or racing applications. The price point of different oils often reflects these variations in base oils and additive quality.
A crucial property of engine oil is its adhesion – its ability to cling to engine parts, ensuring vital protection, especially during engine start-up. Mixing oils can compromise this adhesion due to potential adverse chemical reactions between different formulations. This breakdown in adhesion could lead to increased wear and tear, particularly during cold starts when engine parts are most vulnerable.
Engine oil combats various types of friction, including fluid friction, solid friction, sliding friction, and stick-slip friction. Viscosity, an oil’s resistance to flow, is directly related to fluid friction. Low viscosity oils flow more easily than high viscosity oils. Mixing oils with different viscosities can result in an unpredictable final viscosity, potentially compromising the oil’s ability to provide optimal lubrication across the engine’s operating temperature range.
For optimal engine protection and performance, the best approach is to consistently use a single, high-quality engine oil of the correct grade, as recommended by your vehicle manufacturer. Regular oil changes, adhering to recommended intervals, are far more beneficial than experimenting with oil mixtures. By choosing a suitable oil and maintaining a regular service schedule, you ensure your engine receives the consistent and reliable protection it needs for longevity and peak performance, keeping your car running smoothly for years to come.
