Which one is the right oil for my car? 5W-30, 0W-30 what does it mean?

Which one is the right oil for my car? 5W-30, 0W-30 what does it all mean?


Viscosity Viscosity Viscosity

The title of the oil is meant to communicate the type & thickness of the oil at different temperatures (having the correct thickness a.k.a. viscosity is what this article will be mostly about).

The W in the name 5W-30 standards for Winter and simply means this oil has been tested at colder temperatures.  (Oils without the W in their name i.e. SAE 30 have not been tested for cold weather performance.

At normal operating temperatures (210°F)  5W-30 and 10W-30 will both flow at a SAE viscosity of 30, but under much colder temperatures 5W-30 will flow at an SAE viscosity of 5.   10W-30 will flow at an SAE viscosity of 100-W30 will flow with a viscosity of zero in cold temperatures(meaning freely, with negligible resistance).

Oil that is too thick to flow under cold temperatures results in dry starts.  Oil that is able to stay thin under cold conditions and retain it's film strength results in fewer dry starts and much less engine wear.


The important thing to remember here is that 0W-30, 5W-30 & 10W-30 all flow at the same rate under normal engine operating temperatures.  It’s only under cold start conditions that there is any difference between them.

Regardless of what car you drive, whether it be a BMW, Audi, MiniCooper, Land Rover, Mercedes or Volvo It’s always best to use oil that is recommended for your engine by the manufacturer.  The oil pump and clearances within your engine have all been designed to handle a specific viscosity of oil to lubricate your engine, so using the correct oil with help ensure proper oil flow and all the benefits that go along with it.

What’s an oil additive?  A mixture of chemicals usually used to enhance engine oil performance.

They are often used to achieve additional lubrication, stabilize the oil at higher temperatures, prevent engine wear or reduce fuel consumption.

Examples: Liquid Molly,Lucas conditioner, Bestline.

What’s the different between crude oil, original, full synthetic ,synthetic blend?

Crude oil: The black stuff they find in the ground (not used in cars in this form)

Original/conventional: Refined crude oil consisting of a certain fraction separated by weight.

Full Synthetic: Chemical compounds wholly manufactured and separated into homogenous petroleum molecules of a specific size and weight.

Synthetic blend:  A mixture of conventional motor oil & synthetic.

Synthetic oil offers more protection than conventional oil and can stand higher heat before breaking down.

Not all Synthetic oils are created equal and their formulas/ingredients can vary widely from brand to brand.

While synthetic oils are far more expensive than conventional oil, they usually provide better engine protection than conventional oil or synthetic blends.

If you drive a VW, BMW, Audi, Mini Cooper, Land Rover, Mercedes or Volvo made within the last 15 years, your car probably requires synthetic oil, but always be sure to check with your cars service manual.


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