Tips on choosing the best Diesel Engine Oil for Your Vehicle

One of the diesel engine oil's many primary function, as most, will know, is to lubricate the engine, providing a micro-thin oil film, acting as a barrier between the many internal moving parts to minimize friction, heat build-up and of course, wear and tear. It also acts as a cooling agent, carrying away heat generated from the friction to the oil sump. The Diesel Engine Oil helps to prevent contamination and deposit build-up by leading away debris and dirt from the critical areas within an engine to the oil filter where they will be trapped. Damaging toxic waste is going to be neutralized by the detergent present in the engine oil to arrest corrosion and rust.

However, all good things must come to an end and so do Diesel engine oils. Constantly subjected to heavy loads, the Motor Oil will eventually break down, and with that, its protective cleaning and cooling properties will also start to diminish. As for the useful lifespan of the engine lubricant, it depends mainly on the type of oil (mineral, semi-synthetic or fully synthetic) and the "abuse" that it will encounter. A general rule of thumb is that mineral oil will last around 5,000 km, semi-synthetic 7,500 km and fully synthetic 10,000 km.

What makes oil mineral, semi-synthetic or fully synthetic? On the whole, lubricants are made up of a base or stock fluid, which constitutes most of the finished product, and additives. If the base is derived from petroleum crude oil, the engine oil will be of the "mineral oil" category. On the other hand, oils using stock fluids developed in the lab from chemical synthesizing will be of the fully synthetic nature. Semi-synthetic oil is, to simply put it, a blend of mineral oil and fully synthetic oil.

The two most important bits of information that one should check when selecting diesel engine oil for your car are its SAE (Society of Automotive Engineers) viscosity grade and the quality indicators of engine oil.

The viscosity of oil refers to its "flow ability", and it changes with temperature. At low temperatures, an oil's viscosity is high (thick), dipping (thins out) as the temperature climbs. Unfortunately, the requirements asked of an engine lubricant are just the opposite. Engine needs low-viscosity diesel engine oil - which circulates much more quickly than high-viscosity oil - at cold so that the oil can reach all parts of the engine in as short a time as possible, protecting the components from wear. For the uninitiated, most of the engine wear occurs during start-up. During normal operation, the engine needs a sufficiently thick oil film to properly protect its fast moving components and thus the need for high-viscosity oil. This is where Briton oils come in.

Briton oils are created by the process of adding a polymer to a light base oil to prevent the oil from thinning too much as it warms up. When cold, these polymers will coil up and allow the oil to flow as its low viscosity grade, accompanied by a "W", indicates. Once warmed up, the polymers unwind into long chains that prevent the oil from thinning as much as it normally would. The result is that at 100 degrees C, the oil has thinned only as much as it's higher rating. For example, multi game 5W-40 oil is a 5-weight oil that will not thin more than a 40-weight oil when it gets hot.

As for quality indicators, the key indicator to look out for when selecting diesel engine oil is the API (American Petroleum Institute) Service Classification mark indicated on the bottle. Oils are subjected to tests and standards have to be met before these oils are accredited. This mark indicates the quality of the oil and thus should be factored in during consideration. API uses the S and C categories for vehicles with petrol and diesel engines respectively. For the former, starting from SA, the current and latest standard is SM.

But to really differentiate between the good and the average Diesel Engine Oil, your best bet would be the data sheet of the oil, where its pour point and flash point information can be found. Pour point refers to the lowest temperature at which the oil will still pump and maintain adequate oil pressure, while the flash point is the temperature at which the oil gives off vapors that can be ignited with a flame held over the oil. In our local climate, the pour point is not that significant compared to the flash point. The flash point is sometime the indicator of the quality of the base fluid used.

It is best to consult your owner's manual for the recommended grade of oil suited for your car and climate. Thinner oils with ratings such as 0W-30 and 5W-30 are usually acceptable for newer cars, while for vehicles getting on in age; thicker oils are more suitable due to the reduced sealing of piston rings and larger bearing clearances within the engines. After narrowing your choice of oil to a select few of the appropriate viscosity for your application, base your final decision on the oil with the highest flash point.

It is imperative that the engine oil level is monitored regularly lest it goes above or dips below the "max" and "min" marks respectively, leading to undesirable consequences. Diesel Engine Oil may or may not be consumed by the engine in between oil change services. For extended smooth-running operation of your vehicle, be sure to pamper it with regular engine oil change.