5W30 engine oil is the most common lubricant for modern cars. The operating temperature range of the universal composition is quite wide: the oil does not lose its performance at air temperatures from -25 to +30 degrees.
The synthetic product provides optimal protection for the working elements of the engine, but does this mean that a composition of a different viscosity can be added to the oil? And if so, how to do it correctly? Let’s figure it out.
Which oil to choose: what do the markings 10w40, 0w30, 5w30 mean
Markings 10w40, 0w30, 5w30 mean the main indicator of the composition’s performance, namely, its viscosity. Motor oils are classified into winter, summer and all-season. Winter oils are marked with the letter W (winter).
The number in front of the letter indicates the lower threshold (-35 must be added to the number), at which the oil does not lose its properties, the number after the letter is the maximum air temperature at which the lubricant provides reliable protection. Drivers are advised to remember the low temperature viscosity readings, which indicate the following:
• 0W – the composition works at a temperature of -35 and above
• 5W – oil is designed for a minimum temperature of -30 and above
• 10W – the composition works from -25 and above
• 15W – oil is operated if the air temperature does not drop below -20
There is no need to add or subtract anything to the figure that follows the letter. This is the maximum positive limit at which the synthetic oil retains its viscosity. Marking 10W30 means that the composition is suitable for operation at temperatures from -25 to +30.
Is it possible to mix oils of different viscosities
The answer is unequivocal – it is impossible. If you add oil of a different viscosity to the system or mix synthetic oil with mineral oil, the general characteristics of the composition will change, and the oil will lose almost all of its protective properties.
In addition, oil manufacturers add additives to their formulations that are designed to maintain viscosity, provide additional protection of engine working elements from the accumulation of oxides, prevent rapid coking of the original composition, etc.
So, when two different compositions are mixed, the chemical properties of the oil change, the resulting lubricant will have unpredictable characteristics and can lead to rapid coking of engine parts, the appearance of sediment or engine shutdown.
It is allowed to add oil only of the viscosity that is already in use. The same synthetic composition can be added to the grease marking 5W30. When changing to another oil, it is necessary to drain the lubricant completely and flush the system.
In addition to the main marking on the canister, you can see additional symbols that will tell the specialist a lot. CCS-marking denotes cranking, recovery of oil chemistry after freezing and crankshaft start. The MRV parameter indicates the pumpability of the composition.
The oil pumping time primarily affects the wear of the cylinder block parts. During a cold start, an oil pump enters the system and starts pumping oil through the system. If the degree of oil thickening at low temperatures is high, and the warm-up time is increased, then the engine will operate without the proper amount of lubrication for a critical time.
Synthetic oils of a wide working range have high pumpability rates, in contrast to mineral oils. The composition enters the friction gaps in the first seconds of starting and increases the total engine life.
The CCS cranking characteristic shows the ability of a lubricant to regain its structure if the permissible lower temperature threshold is exceeded. Some oils do not just thicken at low temperatures, but they turn to jelly and no longer regain their chemical protection characteristics.
The marking shows what critical temperatures the composition can withstand so as not to turn into a gel and allow the crankshaft to rotate and start the engine. For all their reliability and versatility, manufacturers are deviating from the rules to produce all-weather oils and recommend using oil depending on the season.
In summer, it is better to use light formulations – this will prevent rapid wear of the exhaust cleaning system and increase the engine’s service life. With a decrease in temperature, it is necessary to switch to winter oil, which has an increased ash content, but provides a smooth start at low temperatures.