Confused about your engine oil? What Diesel Engine Oil is best for you? Know the difference between 5W and 15W diesel engine oils.
Whenever you are choosing the right Lubricants for your vehicle, find the viscosity grades recommended by the original equipment manufacturer (OEM). This information about the right viscosity is usually specified in the manual.
Operating temperature of engines are more or less fixed, so the recommended viscosity is quite consistent for various applications. The main difference becomes the viscosity grade defined by the letter ‘W’ that indicates the starting temperature.
Engine oils have different viscosity ratings, such as 5W-30 or 10W-40. The first number (5W or 10W) represents the oil’s flowability in cold temperatures, and the second number (30 or 40) represents its viscosity at high temperatures. Consult your owner’s manual to find the recommended viscosity for your vehicle.
A 5W viscosity grade requires the lubricant to flow properly at lower temperatures than, 10W viscosity grade, so it is expected to be used at lower starting temperatures. Most OEMs recommend multigrade products, such as SAE 10W-50, because the lubricant flows faster through the engine than a pure SAE 50 even at higher ambient temperatures.
Another important consideration to choose Engine Oil is quality certification like API (American Petroleum Institute). In the case of diesel engine oil quality levels are indicated by the letter ‘C’ along with the second letter according to the alphabet sequence ‘A’ to ‘J’ for the lowest to highest performance. There are some specific OEM performance requirements for the condition of the engine’s warranty.
Sometimes you can use 5W viscosity instead of recommended 10W or 15W to provide faster lubrication to the engine during start-up. The formulation of 5W uses lighter base stock, and it has more evaporation than 10W or 15W. So, the cost of using 5W could be a little higher than 10W or 15W.
You can make a decision to use synthetic lubricants with the same viscosity and quality claims. Normally fully synthetic lubricants offer better protection and detergency than other conventional mineral oils.
If you are confused about the exact viscosity and quality recommendation, you could go for 15W viscosity that works well in any situation.
Below figure shows the general reference for viscosity selection based on temperatures.
