What oil to use?

[renegade_wolf]

Been searching for awhile and can't fina a answer seeine some places.saying 0w-20, 5w-30, 10w-30 and 10w-40.
Have a local E171 time for a oil change. Can't find anywhere in the engine bay or in the car that states what type of oil to use. Meh old Nissan used to have it on the oil cap.
What grade to buy? Car low mileage under 30000km.

[*KRONIK*]

These usually run on 5 or 10w30

[renegade_wolf]

Thanks very much for the reply.

[martian]

This question is much more complicated than “I use such and such oil.”

Let's understand the meaning of the name of the oil. The type of oil based on viscosity is divided into winter, summer and all-season.
Winter is designated SAE 5W (Society of Automotive Engineers), summer is SAE 40, and all-season is SAE 5W-40. Nowadays you rarely find winter or summer oil anywhere, so let’s move straight to all-season.

5W-30 is often used, so let’s look at it as an example.
The first number in the designation (5W) is low-temperature viscosity, which means that a cold start of the engine is possible at a temperature not lower than −35 °C (-31°F) (i.e., 40 must be subtracted from the number in front of W).

If we subtract 35 from the number in front of W, then we get the minimum “cranking” temperature of the engine - the value at which the oil will work correctly in the internal combustion engine. As the temperature drops, the oil becomes thicker, and it is more difficult for the starter to crank the engine during a cold start.

If you live in a region where the air temperature in winter rarely drops below −20 °C (-4°F), almost any oil will suit you for this parameter. Another question is the condition of the car’s starter and battery. If they are worn out, it will certainly be easier for them to start the engine at -20°C (-4°F) with 0W-30 oil than with the thicker 15W-40.

The second number in the designation (30) is high-temperature viscosity. This is a composite indicator indicating the minimum and maximum oil viscosity for this class at 100°C (212°F) and HTHS at 150°C (302°F). The higher this number, the higher the viscosity of the engine oil at high temperatures. Whether this is good or bad for your engine, only the car manufacturer knows.

If you have a new car and the mileage is less than 50% of the planned life, the bearings will work well even with low viscosity. In this case, a product of the 5W-30 or 0W-20 category will suit you.
If the mileage exceeds 50% of the planned resource, it is better to choose oil with an index of 5W-40 or higher. This is explained by the fact that in an engine with a relatively high degree of wear, the gaps between parts increase, so it makes sense to use a more viscous lubricant. As I understand it, this is not your case.

[martian]

But if you are asking about such a question, it means you most likely do not know what kind of oil is currently in the engine. This means you need to complete the entire procedure of draining the oil with replacing the oil filter, and also flush the engine to get rid of traces of the old oil and only then fill in new oil. If you have never done this, you can watch YouTube guides or read articles, like this one, for example, or this one, everything is clearly explained there. But personally, I would recommend contacting a car service so that they can do it, and you can see how it happens.

[martian]

Only after I described everything in super detail, I realized that this is an old thread and it’s probably not relevant to people anymore *facepalm*
Admins, I think you will see this thread. If this is a useful answer, should it be moved to a separate new topic, for example for beginners?