What are the classification levels and models of diesel engine oil?
3 Answers
Here are some classifications of diesel engine oil levels and their applicable models: 1. CE: Engines operating under conditions of low speed and high load, or high speed and low load. The letter 'C' at the beginning represents diesel engine oil, and the further the letter is in the alphabet, the higher the quality grade of the oil. Generally, CD-grade oil is sufficient for most diesel engines. 2. CD: Turbocharged diesel engines. 3. CG-4: High-speed, heavy-duty, long-cycle operation diesel engines. 4. CH-4: Bimetallic piston diesel engines. 5. CI-4: Diesel engines with low-temperature exhaust gas recirculation systems.
I've always driven diesel vehicles, and the classification of diesel engine oil is quite important. The API classification is key, divided into the C-series, such as CF-4, CH-4, CJ-4, CK-4, and FA-4. CF-4 is the older generation, still in use but rare now. CH-4 is designed for high-load engines, CJ-4 meets earlier emission requirements, CK-4 is the current mainstream, suitable for most vehicles, and FA-4 reduces viscosity to save fuel. Viscosity grades are also divided into two types, SAE such as 15W-40 or 10W-30, where W stands for winter startup performance—the smaller the number, the easier it is to start in cold weather. When choosing, refer to your vehicle's manual; different engines require different grades. Like the time I used the wrong one, the engine shook badly, costing a lot to repair. Remembering these classifications can avoid excessive wear. Pay attention to the oil color and change it regularly during maintenance, and the car will run much smoother.
As someone who frequently works on diesel vehicles, I know that common diesel engine oils are classified by API ratings and SAE viscosity. Among API C categories, CK-4 is currently the most popular as it supports DPF emission systems, while FA-4 has lower viscosity and is suitable for newer engines to improve efficiency. Viscosity grades like 20W-50 offer better protection at high temperatures, whereas 5W-40 ensures faster cold starts. Many still use outdated grades like CD, which can lead to carbon buildup and component damage—I've encountered cases of engine knocking due to incorrect oil grades. During diagnostics, always check oil pressure and grade markings; manuals typically specify CJ-4 or newer. Never switch oils arbitrarily—mismatched viscosity can cause oil film breakdown and premature overhaul. In maintenance, inspecting oil cleanliness and grade is routine; using the correct grade long-term extends engine life.
