What is the difference between ACEA-C3 and A3B4 engine oils?

[VonJohnny]

Both C3 and A3B4 engine oils are standards rated by the European Automobile Manufacturers' Association (ACEA). The main difference between them lies in their series classification. A3B4 engine oil is suitable for gasoline and light-duty diesel engines, while C3 engine oil is designed for catalyst-equipped engines. Below is detailed information about automotive engine oils: 1. Overview: Engine oil, also known as engine lubricant, is referred to as Engine-oil in English. It has a density of approximately 0.91×10³ (kg/m³). It serves to lubricate and reduce friction in the engine, assist in cooling, seal against leaks, prevent rust and corrosion, and provide shock absorption. 2. Composition: Engine oil consists of two main components: base oil and additives. The base oil is the primary component of the lubricant, determining its fundamental properties. Additives are used to compensate for and improve any deficiencies in the base oil's performance, as well as to provide new characteristics, making them an essential part of the lubricant.

[NoahRose]

With years of research into oil standards, I've found that ACEA C3 and A3B4 primarily differ in ash content and vehicle applications. A3B4 is a traditional high-performance oil with higher ash content (around 1.5%), suitable for older gasoline and light-duty diesel vehicles like classic sedans. C3 is a modern low-ash oil with ash content limited to below 0.8%, designed for newer vehicles equipped with diesel particulate filters (DPF) to protect exhaust systems from clogging. Viscosity differs too: A3B4 has a high-temperature high-shear (HTHS) viscosity of at least 3.5mPa.s, making it suitable for aggressive driving; C3 is similar but has stricter controls on environmental pollutants. Choosing the wrong oil may lead to DPF failure or engine wear—always check your owner's manual for compatibility. For fuel-efficient vehicles, C3 is the better choice.

[ElleLee]

As a car owner with over a decade of experience, I've personally experienced the importance of engine oil selection. ACEA C3 and A3B4? A3B4 is a universal oil suitable for most older gasoline and diesel vehicles, with slightly higher ash content but better power response; C3 must be used in modern vehicles with exhaust treatment systems, otherwise it may clog the DPF and increase maintenance costs. The core difference lies in ash content: C3 has ultra-low levels to protect the environment, while A3B4 leans towards practicality. I once used the wrong oil and triggered a warning light—a profound lesson. When buying engine oil, don't just look at the price; matching the oil to your vehicle type is key to extending engine life.

[Alfie]

Newbies often confuse ACEA C3 and A3B4 during oil changes: C3 has very low ash content, suitable for new cars with exhaust treatment systems, such as eco-friendly SUVs; A3B4 is a general standard with higher ash content, better suited for older engines. Simply put, if your car has a DPF, use C3 to avoid clogging; otherwise, A3B4 is safe. Never mix them—always check the oil label to confirm the standard. Regularly consult your manual to choose the right oil, protecting performance while saving money.