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Frequently Asked Questions
Frequently Asked Questions
  • Can I mix two different types of oil?
    • Lubricants are always optimized to meet the requirements of international classifications such as API, ACEA, etc. There are many ways of formulating a specific type of lubricant. Mixing two oils that have equivalent properties will not pose a problem, but under such circumstances the final performance of the oil cannot be guaranteed. All the engine oils (whether petrol or diesel, mineral or synthetic) are mixable. However, blending two oils lowers the quality of the superior oil.

  • What is the significance of the color of the oil?
    • The color of the oil has no special meaning, but it depends on a number of factors such as the refining process and the types of base oils, additives and crude oil used. The oil might turn a shade darker after use because it contains a number of suspension particles. The reason for this color change is that the oil cleans the engine of particles and other deposits produced by the high temperature combustion. These particles are then kept in suspension to avoid depositing them on the engine’s surface.

  • Can I use a diesel engine oil in a petrol engine, and vice versa?
    • Petrol and diesel engines have different lubrication requirements. During development, lubricants undergo a number of tests, some common to diesel and petrol engines and others specific to one or the other type, that categorize their performances. At the end of this process, they are awarded an API or ACEA/CCMC compliance standard. These specifications characterize the acceptable functioning of the lubricant in each type of petrol or diesel engine. Lubricants for four-stroke engines usually comply with both petrol and diesel specifications. For example, an API SJ/CF lubricant meets petrol specification SJ and diesel specification CF. But this does not necessarily mean that it will perform in the same way in both petrol and diesel engines. This is why GS Caltex has developed a specialized range of lubricants, optimized either for petrol or for diesel engines.

  • How often should the engine oil be topped up?
    • The engine oil level should be checked regularly. An engine in good condition consumes between 0.2 - 0.5 liters of oil every 1,000 kilometers. Accordingly, it is natural that an engine consumes a small amount of oil, which can be offset by top-ups between oil changes; however, excessive need for top-ups can be an indication of mechanical problems such as leakages, etc.However, successive top-ups are no substitute for an oil change.

  • What is the duration after which the engine oil should be changed?
    • Engine oils need to be changed periodically else they lose their protective properties and no longer enhance the performance of the engines.The engine oils should be changed according to the manufacturer`s recommendations. The frequency recommended by the manufacturer may be modified based on: the lubricant used, the vehicle use (country, city, and highway), thermal and mechanical requirements.
      Never drive with an oil level below the minimum mark on the dipstick as it causes more rapid circulation of the fluid and accelerated wear.It is recommended to check the level regularly every 1000 km and especially before a long trip.

  • What are additives and why are they used?
    • Additives are chemical compounds which, when added to base oils, improve the performance of the lubricants allowing them to respond to the demands of the modern engine.

  • What does API stand for?
    • API is the short form for American Petroleum Institute, USA, which develops/certifies engine oils with active consultation with various vehicle manufacturers. They assign grades like API CC/CD/CF/CG/CH-4/CI-4/CJ-4. etc. for commercial vehicles using HSD as fuel & SF/SG/SJ/SL/SM/SN for gasoline vehicles with petrol engines. The higher the alphabet, the better is engine oil, e.g. SN is better than SJ or SL etc. and CI-4 is better than CH-4 or CF-4 etc.

  • Why choose a Synthetic oil for your vehicle?
    • Semi-synthetic and synthetic oils are made from non-conventional bases using sophisticated chemical processes which confer special properties to the finished product. The high level of viscosity of the base oils used give the finished lubricant a remarkably stable viscosity whatever the temperature. This property is one of its major advantages over mineral oils, made from conventional bases which require a greater number of additives in order to improve viscosity. The stability of lubrication in all temperatures guarantee optimum efficacy in the cold-starting phase which is particularly demanding on the engine as well as under conditions of extreme heat. Synthetic-based lubricants show greater resistance to oxidation, which enables them to last longer thus guaranteeing longer engine life. The use of non-conventional bases permits the elaboration of more fluid lubricants, without being more volatile; resulting in reduction of oil consumption. Thus choosing a synthetic based oil is a technologically advanced choice that ensures greater efficacy, longevity and controlled oil consumption.

  • What is the difference between Synthetic and Mineral oils?
    • Synthetic lubricants are made up of molecules that have been modified under complex chemical processes and allow for enhanced performance under extreme conditions of temperature, pressure and forces. Mineral lubricants are composed of molecules present in crude oil that are separated in the distillation process at a refinery.

  • What is a multi-grade engine oil?
    • The oil which meets more than one SAE specification is called a multi-grade engine oil eg. SAE 20W40 explains that this oil must pass the viscosity grade requirement for both SAE 20W and SAE 40. The temperature range the oil is exposed to in most vehicles can be wide, ranging from cold temperatures in the winter before the vehicle is started up, to hot operating temperatures when the vehicle is fully warmed up in hot summer weather. A specific oil will have high viscosity when cold and a lower viscosity at the engine`s operating temperature. The difference in viscosities for most single-grade oils is too large between the extremes of temperature. To bring the difference in viscosities closer together, special polymer additives called viscosity index improvers, or VIIs are added to the oil. These additives are used to make the oil a multi-grade motor oil, though it is possible to have a multi-grade oil without the use of VIIs. The idea is to cause the multi-grade oil to have the viscosity of the base grade when cold and the viscosity of the second grade when hot. This enables one type of oil to be generally used for the entire year.

  • What do you mean by the viscosity of the oil ?
    • Viscosity is a measure of the oil’s resistance to flow. A high viscosity implies a high resistance to flow while a low viscosity indicates a low resistance to flow. Viscosity varies inversely with temperature. Viscosity is also affected by pressure. Higher pressure causes the viscosity to increase along with the oil`s load-carrying capacity. A good quality lubricant has a steady viscosity under different temperatures and usage conditions for a longer period of time.

  • What is role of a lubricant?
    • Lubricants have five major roles to play at the point of friction in machines and equipment. 

      1. Frictional wear Prevention: Lubricants form a layer of lubricating film on a metal surface to change metal friction into fluid friction, thereby lowering the frictional factor to prevent power loss and frictional wear.
      2. Anti-Rusting: Lubricants prevent rusting by blocking the contact of metal with oxygen through the layer of lubricating film on the surface of the metal.
      3. Stress Dispersion: Lubricants act to equally disperse pressure throughout the fluid caused by heavy weight load and shock applied to the frictional surface. 
      4. Cooling: Lubricants prevent overheating by absorbing and discharging frictional heat created by the operation of frictional parts. As the equipment is overheated, the oxidation of oil quickens, and thus the lubricants also indirectly act to prevent oxidation. 
      5. Sealing: Lubricants prevent soil, dirt and water from mixing with the frictional surface and acts as a seal to prevent pressure loss. Lubricants have excellent performance properties in cooling and stress dispersing, whereas greases have superior sealing and rust preventing qualities.