2-Engine oil density factor SAE:
Another factor, which has essential role in determination of engine oil, is the type of engine oil regarding its viscosity.it means that how much should engine oils density be in order to have best performance according to weather conditions and engine performance Society of automative engineers or briefly SAE have designated a particular standard to determine engine oils viscosity which eases the process of diagnosing engine oil and you can easily purchase suitable engine oil for your vehicle Of course it is important to consider that with recent advancements in technology multi grade engine oils have entered market which demonstrate effective performance in various tempretures If you look precisely at engine, oils this index is available in the following forms
(SAE: 10W-40, 05W-40, 05W-30, 10W-30, 20W-50, 0W-20,)
(SAE: 10W-40, 05W-40, 05W-30, 10W-30, 20W-50, 0W-20, …)
Engine oil density
First letter before letter W demonstrates engine oils viscosity in low tempreture (winter), the lesser this number is the more diluted engine oil becomes. This number plays an essential role in first start in cold days of winter. Because,for lubricating engine in this situation engine oil must be far more diluted in order for lubrication to happen correctly, for cold weather in winter may cause engine oil to become denser which brings about damage to engine and cause corrosion of segments as a result of wrong lubrication Therefore this number reduces engine oil will be extra diluted and ensures you that in first start all engine parts will be lubricated and engine starts working effortlessly The bigger the number the denser the engine oil.
for example if youre living in a city like Ahwaz in which the tempreture could rise up to +40 centigrade degree it is better to choose an engine oil, which does not loose its lubrication features according to weather and engines heat It means that its density has to be adequate because engine oil might become completely diluted in this condition and therefor loose, its performance.so it is better to pay attention to the table in the following, which indicates engine oils tempreture range, based on viscosity
Engine oil density
For example, W-40 10 engine oil is applicable according to table in tempreture range of -30 to +40-centeigrade degree; therefore using diagram above you can easily choose engine oil that matches weather conditions that youre living in. For example Tehrans and its vicinities, tempreture in summer is in range of -10 to +40-centigrad degree. Therefor, according to this tempreture, that type of engine oil is suitable which has high viscosity in high tempreture .
as a result utilization of engine oils with viscosity index 15 W40 or 10 W-40 is suggested in this tempreture range For cold climates, it is better to use engine oils, which are more thin and diluted or in other words have lower viscosity so in a cold day, the motor will be able to start without difficulty and no damage will occur to engine. If viscosity happens to be high engine oil might not lubricate properly in first start and that brings about damage to your car engine.Ardebil,Shahrekord,Tabriz,Hamedan,Sanandaj are of cities in which engine oils with lower viscosity is more advised.for example engine oils such as W-20, 0W-30,0W-40, 5W-30,05W-40….. Are appropriate for these cities
For cities located in warm areas of the country, those engine oils are suitable that have high viscosity For example for cities like Bandar abbas, Sistan balouchestan, Ahwaz, Isfahan, Kerman, and …. It is better to use engine oils that have high viscosity and density in high tempreture. For instance, engine oils such as W-50, 10W-40, 20W-50, and 15W-50… are wise choise for these cities. Therefore, it is better to pay attention to this significant factor before purchasing your engine oil