Viscoisty is the resistance of oils against flow, and it is one of their most significant properties. Viscosity is measured at 40 °C for industrial oils and at 100 °C for automotive oils. Unit is shown as mm²/s or cSt.
Viscosity numbers show fluidity of oils. As the numbers go down, fluidity of oils goes up.
In classification of engine oils, initial number shows the fluidity of oil under cold condition and ends with W (for Winter). Second number is the value that represents the oil’s fluidity under working temperature - that is high temperature.
For example, 5W-30 engine oil flows easier than 10W-30 engine oil during first start while 10W-30 oil flows easier compared to 10W-40 on running engine temperature.
Engine oil disperses and embodies the soot particulates, prevents them sticking on metal surfaces and cleans carbon residuals thanks to anti-oxidant, anti-corrosion and detergency additives. This is why engine oil darkens and looks dirty.
Mineral oils are directly derived from refining the crude oil whereas synthetic oils are obtained after refining and distillation followed by a chemical reaction. Synthetic oils are more pure and of higher quality than mineral oils, and they provide better protection and performance under high temperatures by means of special molecules. Synthetic oils provide easier flowability and pompability under cold weather conditions, more stable film resistance under extreme pressure, and longer oil change intervals under tough working conditions.
Running engine for long duration at high rotation and aggressive driving; engine’s oil burning more than usual because of loosing of pistons within time; wear and tear on ring, main bed, pressure relief valve bed or pistons; any deficiency in oil pump, leak in motor seal rings; accumulation of soot and carbon on the oil rings; inappropriate oil use; crack on the lower crank case; loose cap are some of the many reasons that cause decrease in engine oil.
API, which stands for American Petroleum Institute, letter “S” signifies that oil should be used in petroleum engines. There are 12 different classification according to the performance levels – SA, SB, SC, SD, SE, SF, SG, SH, SJ, SL, SM, SN. According to the API classification, the further the letter is, the higher requirements oil specification is. SA, SB, SC, and SE class oils are used in vehicles manufactured between 1930 and 1979 while today mostly SJ, SL, SM and SN class oils are preferred.
Recommended API classes for petroleum engines: API SJ – not older than 2001 make year, API SL – not older than 2004 make year, API SM – not older than 2010 make year, and API SN – 2011 and onwards make years.
In such cases where inappropriate oil against the performance and technology of vehicle is used, low vehicle performance and technical problems along with overheat because of high friction. Wrong oil selection shortens motor parts’ life, and energy that comes out of friction causes high fuel consumption.
Even though there are different antifreeze production methods, they are basically composed of glycol and inhibitors. Mono Ethylene Glycol (MEG) is mostly preferred for glycol. Depending inhibitor’s being organic or inorganic, they get the name organic or inorganic antifreeze. Also, coloring agents like green, blue, yellow, red, pink are used to detect antifreeze leakage. Usually blue and green colors are used for inorganic inhibited antifreeze while red and pink are for organic inhibited antifreeze. Organic inhibited red antifreeze is 3 times more durable than inorganic inhibited blue antifreeze. But, this does not mean that we can extend antifreeze life when we use red color one for every vehicle. Vehicle or equipment manufacturer guidance, vehicle/equipment manufacture year are information needed to define the right product.
Antifreeze should be changed every year. Organic inhibited antifreezes are durable for longer and can be changed in 3 years.
Greases are semi-solid and solid lubricants that are composed of base oil, soap (thickener), and additives which enable enrichment of their forming properties.
Greases are commonly used in machine parts and bearings, vehicle motors, loaders and tractors, motorcycles, and industries for machinery lubrication. They are especially used for lubricating 80% of the rolling linings, and also for mechanical and thermally light/medium/heavy load rolling/sliding ball bearings, chassis, springs, multipurpose semi-solid lubrication of electric vehicles.
Usually, shelf life of oil depends on its properties. Shelf life of engine oils, transmission oils and tractor oils stored in interior areas at 20°C is five years. Hydraulic oils and grease can be stored three years while oils that contain emulsifiers should not be stored more than 6 months.
Insufficient lubricant level in engine bed causes friction. With friction, crank shaft, beds and piston connecting rod are damaged. These parts when left out with inadequate oil cannot move and they get stuck. Engine failure that is caused by deformed engine parts is called engine “seizure”.
Low levels of oil and coolant are the major reason for an engine seizure. When engine does not sufficient oil or oil pump does not function for any reason, engine seizure occurs.