What does CF-4 diesel engine oil mean?

[VonVivienne]

CF-4 diesel engine oil: Established in 1991. Used in high-speed four-stroke diesel engines produced after 1990. It outperforms CE in terms of fuel consumption and piston deposit control, and can replace CE. This type of oil is particularly suitable for heavy-duty trucks operating on highways. Extension: API (American Petroleum Institute) categorizes automotive engine oils into S - gasoline engine oils and C - diesel engine oils. The 'C' stands for Commercial, service; Compression, compression ignition. Diesel engine oil specifications have evolved from the initial CA to the current highest-grade CI-4. The sequence includes CA, CB, CC, CD, CD-Ⅱ, CE, CF, CF-Ⅱ, CF-4, CG-4, CH-4, CI-4, where CD-Ⅱ and CF-Ⅱ are for two-stroke diesel engines.

[DelJesse]

CF-4 is an API specification certification mark for diesel engine oil, simply put, it's an old standard for specialized diesel engine oil certified by the American Petroleum Institute. The 'C' stands for oil intended for diesel engines, 'F' represents the performance level, and '4' indicates suitability for four-stroke engines. This type of oil was particularly popular in the 1990s, mainly used in older National III diesel vehicles without aftertreatment systems, such as early Cummins engines. It could withstand high-sulfur diesel environments and provided good high-temperature detergency and bearing corrosion protection. However, nowadays diesel vehicles use CK-4 grade oil, and CF-4 has basically been phased out, occasionally seen in agricultural machinery repair shops.

[LeGrant]

As a craftsman with over a decade of experience in auto repair, I'm extremely familiar with the CF-4 rating. Back when servicing those old diesel vehicles, this API specification was the go-to standard for oil changes. Its most distinctive feature was the red-background, white-lettered circular certification logo, primarily controlling soot dispersancy and anti-wear performance. I recall it being particularly suitable for high-compression direct-injection diesel engines - many Steyr heavy-duty truck engines using this viscosity could run 200,000 kilometers without major overhauls. The main reason it's been replaced by CJ/CI grades is due to emission upgrades, as modern diesel exhaust treatment systems can't tolerate the high sulfur and phosphorus content in older lubricants.

[OBrianna]

When you see the CF-4 marking on an oil can, it basically indicates that this is a specialized lubricant designed for mechanical pump diesel vehicles from the 1990s. Its core functions address two major challenges posed by high-sulfur diesel at the time: first, preventing sulfuric acid corrosion of copper-lead bearing shells caused by combustion, and second, controlling the impact of carbon deposits on turbochargers. Interestingly, while CF-4 oil has virtually disappeared from trucks in Europe and America, you can still find mining vehicles in certain African regions using it. Here's an interesting tidbit: oil grades ending with '-4' all indicate compatibility with older engines equipped with EGR (Exhaust Gas Recirculation) systems.