Frequently Asked Questions

Yes, in most cases, there is no problem in moving to a higher operating temperature viscosity. At Greyhound Lubricants, we believe that having a higher viscosity at operating temperature i.e., SAE 5W-40 viscosity will be of benefit to your engine over 5W-30, particularly in African, hot operating environments. Such oil choice will provide for a slightly thicker oil film between the engine components when the engine is at operating temperature. This lowers frictional heat which causes wear and hence provides better protection for the engine.

• Greyhound HM mineral hydraulic oil: Mineral oil with anti-foaming, anti-corrosion, anti-rust and anti-wear performance.
• Greyhound HV mineral hydraulic oil: Mineral oil with additional anti-foaming, anti-wear, anti-corrosion, anti-rust performance having a viscosity index > 140; used for hydraulic circuits subject to strong temperature variations as well as load constraints and very high pressures and perfect for heavy-duty equipment and African hot weather exposure.

While synthetic oil might imply this product is man-made, it’s slightly misleading. Yes, these oils are modified (chemically converted) and purified according to processes developed in a laboratory by the research and development engineers, but these recipes are then turned into processes to mass-produce synthetic oils.

Advantages of synthetic oil over the mineral type

• Synthetic has high-quality additive packages, resulting in increased performance under extreme conditions;
• It is a cleaner oil thanks to most impurities having been removed;
• Free-flowing in cold conditions, as the wax-forming deposits are removed;
• Thermal stability is improved at high temperatures, which prevents oxidation;
• Longer service intervals are possible owing to the mentioned benefits.

The process of creating synthetic oil is more complex and costly than mineral oil and those costs are passed on to the consumer. Apart- (or semi-) synthetic oil is a blend of mineral and synthetic oil. To use the term “part synthetic” on the packaging material, the contents must include at least 10% synthetic oil.

A basic lubrication system includes the following:

• Sump or oil pan, where the oil accumulates in a wet-sump application (dry sumps are for race cars, in which cornering forces may move the oil away from the oil pick-up).
• Oil pick-up that feeds the oil pump.
• Oil pump that supplies the oil galleries with the lubricant at pressures ranging from two to six bar depending on engine speed and application.
• Oil filter that’s tasked with removing debris from the oil.
• Oil galleries, supplying the moving parts with oil, including the main and big-end bearings, as well as the valve train (cylinder walls are wet mostly because of spraying or splashing). The highest contact forces are on the lobes of the camshaft and can be as high as 10 tonnes per square centimetre – about the same as 10 light hatchbacks on an area the size of the sole of a stiletto’s heel.
• Oil pressure switch to inform the driver when oil pressure is lost. If all oil pressure is suddenly lost, damage occurs almost immediately.

It is advised to check the engine’s oil level after the engine has been stopped for a few minutes. As the engine and oil should be fairly hot, which would make the oil thinner (low viscosity), the drain-down time of the oil to the sump would be a few minutes.

The best way to choose engine oil is to check your owner’s manual for the vehicle you drive.

An owner’s manual will provide a particular API Specification. This will look something like CF/SF 15W40. CF/SF gives the specifications for both diesel–compression and petrol – spark. The higher the 2nd letter the higher the grade of the oil. 15W40 indicates that describes the viscosity of the oil.

It is better to top up with any available oil, even if it has a different viscosity grade in an emergency rather than risking running with little or no oil. It is preferable to top up with the same viscosity of the oil, if possible.

Therefore there is no problem topping up with mineral if you run mineral oil and can only top up with a better/worse grade of oil as it will proportionally increase/decrease the qualities of the engine oil.

Viscosity indicates the thickness of the oil. Water has low viscosity while oil’s viscosity is much higher. The thinner the oil, the better lubrication your engine gets as the temperature of an engine increases, the engine oil tends to get thinner. As a result, our entry-level Monograde Oil is suitable for warmer, African climates, while European countries with a colder climate will have decreased lubrication in cold conditions, as engine oil is thick and will only start lubricating your engine as your engine gets warmer. A monograde oil (i.e. G-Base SAE 40) may be effective at high temperatures but is too thick at low temperatures.

This is why additives that modify the viscosity were developed to lower the oil’s viscosity at low temperatures and increase it at high temperatures. For example, G-Power SAE 15W-40 oil behaves like an SAE 15 monograde oil at 40 degrees Celsius, but like an SAE 40 oil at the general operating temperature of 100°C.

We offer many different specifications and viscosities of engine oil. Please feel free to contact us for any advice or for a range that might not be included on our website.

Most oil is refined from crude oil (although deriving the liquid from gas and coal is also possible) in a process called hydrocracking. Hydrogen and a catalyst are added to the heavy oil in a process that takes place in up to four reactors under high pressure and temperature. The long hydrocarbon molecules are then broken down to produce different chain lengths for various products, including base oils and fuels.

Many other processes take place at the refinery plant (for example, desulphurisation), but we’re interested in the final five groups of base oils as classified by the American Petroleum Institute (API). Groups one and two are categorised as mineral oils, and groups three to five as synthetic. The base-oil performance increases with the group number. Oil companies blend the base oils in specific ratios to create the different engine-oil ranges.

Each manufacturer adds additive packages during the blending process to meet the performance criteria of each product. These additives strive to:

• Enhance the viscosity rating;
• Lower the pour point in cold temperatures;
• Slow down oxidation at higher temperatures;
• Remove gases from the oil (anti-foaming);
• Clean the moving components (detergents);
• Keep contaminants suspended in the oil and prevent them from settling on the metal surfaces (dispersant);
• Minimise wear;
• Inhibit corrosion;
• Protect engine components under extreme pressure.

Because these additives are added during the process of creating the oil, Bowen is sceptical about any possible benefits of then adding further aftermarket additives to your car’s oil: “It is like adding ingredients to a cake after it was baked.”

While synthetic oil might imply this product is man-made, it’s slightly misleading. Yes, these oils are modified (chemically converted) and purified according to processes developed in a laboratory by the research and development engineers, but these recipes are then turned into processes to mass-produce synthetic oils.

Advantages of synthetic oil over the mineral type

• Synthetic has high-quality additive packages, resulting in increased performance under extreme conditions;
• It is a cleaner oil thanks to most impurities having been removed;
• Free-flowing in cold conditions, as the wax-forming deposits are removed;
• Thermal stability is improved at high temperatures, which prevents oxidation;
• Longer service intervals are possible owing to the mentioned benefits.

The process of creating synthetic oil is more complex and costly than mineral oil and those costs are passed on to the consumer. Apart- (or semi-) synthetic oil is a blend of mineral and synthetic oil. To use the term “part synthetic” on the packaging material, the contents must include at least 10% synthetic oil.