In the crankcase
In the crankcase of a vehicle engine, motor oil lubricates rotating or sliding surfaces between the crankshaft journal bearings (main bearings and big-end bearings), and rods connecting the pistons to the crankshaft. The oil collects in an oil pan, or sump, at the bottom of the crankcase. In some small engines such as lawn mower engines, dippers on the bottoms of connecting rods dip into the oil at the bottom and splash it around the crankcase as needed to lubricate parts inside. In modern vehicle engines, the oil pump takes oil from the oil pan and sends it through the oil filter into oil galleries, from which the oil lubricates the main bearings holding the crankshaft up at the main journals and camshaft bearings operating the valves. In typical modern vehicles, oil pressure-fed from the oil galleries to the main bearings enters holes in the main journals of the crankshaft. From these holes in the main journals, the oil moves through passageways inside the crankshaft to exit holes in the rod journals to lubricate the rod bearings and connecting rods. Some simpler designs relied on these rapidly moving parts to splash and lubricate the contacting surfaces between the piston rings and interior surfaces of the cylinders. However, in modern designs, there are also passageways through the rods which carry oil from the rod bearings to the rod-piston connections and lubricate the contacting surfaces between the piston rings and interior surfaces of the cylinders. This oil film also serves as a seal between the piston rings and cylinder walls to separate the combustion chamber in the cylinder head from the crankcase. The oil then drips back down into the oil pan.45
Motor oil may also serve as a cooling agent. In some constructions oil is sprayed through a nozzle inside the crankcase onto the piston to provide cooling of specific parts that undergo high temperature strain. On the other hand, the thermal capacity of the oil pool has to be filled, i.e. the oil has to reach its designed temperature range before it can protect the engine under high load. This typically takes longer than heating the main cooling agent ? water or mixtures thereof ? up to its operating temperature. In order to inform the driver about the oil temperature, some older and most high performance or racing engines feature an oil thermometer.
Due to its high viscosity, motor oil is not always the preferred oil for certain applications. Some applications make use of lighter products such as WD-40, when a lighter oil is desired, or honing oil if the desired viscosity needs to be mid-range.6
Give the car to a professional mechanic
Each car from time to time need of repair - minor defects is quite a normal thing. It happens also that the car must travel a serious review. Whatever the situation, you might want to have a trusted mechanic who well knows his job. But how to find it? A good solution is to ask your friends if they could recommend someone suitable. Reputation in such a case often provides the highest quality services. In addition, if a mechanic can quickly find the cause of problems with the car and is able to immediately determine the extent of repairs needed and valued service and the cost of parts - most likely we are dealing with a trustworthy expert.
Motor oil, engine oil, or engine lubricant is any of various substances (comprising oil enhanced with additives, for example, in many cases, extreme pressure additives) that are used for lubrication of internal combustion engines. The main function of motor oil is to reduce wear on moving parts; it also cleans, inhibits corrosion, improves sealing, and cools the engine by carrying heat away from moving parts.1
Motor oils are derived from petroleum-based and non-petroleum-synthesized chemical compounds. Motor oils today are mainly blended by using base oils composed of hydrocarbons, polyalphaolefins (PAO), and polyinternal olefins2 (PIO), thus organic compounds consisting entirely of carbon and hydrogen. The base oils of some high-performance motor oils contain up to 20% by weight of esters.3