EXPRESS TURBO 15W40 API CH-4

It seems like you're mentioning information about a specific type of diesel engine oil. "15W40" refers to the oil's viscosity grade, while "API CH-4" indicates its performance classification set by the American Petroleum Institute (API).

Here's a breakdown of what each of these specifications means:

15W40: This is a viscosity grade classification for engine oils. The "15W" part indicates the oil's viscosity at low temperatures, with the "W" standing for "winter." The lower the number, the better the oil flows in cold conditions. The "40" represents the oil's viscosity at operating temperatures, which is a measure of its resistance to flow when the engine is hot. In summary, 15W40 is a multi-viscosity oil suitable for a wide range of temperatures, making it suitable for both cold starts and high-temperature engine operation.
API CH-4: The American Petroleum Institute (API) has established a set of standards for classifying engine oils based on their performance characteristics. "CH-4" is one such classification, indicating that the oil is suitable for use in high-speed, four-stroke diesel engines, particularly those with turbochargers. CH-4 oils are designed to provide enhanced control over piston deposits, wear, and oil consumption, making them suitable for older diesel engines.
Brand: EXPRESS TURBO: This appears to be the brand name of the diesel engine oil. Different manufacturers produce engine oils with varying additives and formulations, even if they meet the same specifications. The "EXPRESS TURBO" brand likely has its unique formulation and is marketed for use in diesel engines requiring the specifications mentioned (15W40 and API CH-4).
It's important to note that the information provided is based on the details you mentioned. When selecting engine oil for your vehicle, it's crucial to follow the manufacturer's recommendations found in the owner's manual to ensure that you are using the correct type and grade of oil for your specific engine.