oil bottle

Here are some common questions about engine oil:

  • Does the type of engine oil I put in really matter?
  • Can I change the brand of oil I use?
  • What do the numbers mean?

All oil today is called “paraffin-based oil.” That means the oil has the ability to capture dirt—this is one of its jobs. When an oil change is performed, we drain the oil from the vehicle and dirt goes with it.

Manufacturers have made changes to the oil for use in lubricating their specific engines. The car industry used to recommend oil based on geographic conditions. If you lived in a cold climate, like Alaska, thinner winter oil was recommended. If you lived in the warmer southern states, heavier oil might be recommended.

All that has changed due to the tolerances built into cars by the manufacturers. Today it is more important than ever that you pay attention to the type of oil the manufacturer recommends.

The label on a bottle of oil provides information about that oil. Most people examine the weight of the oil first. Is it 5W-30? 10W-30? What does that even mean? Well, the “W” stands for winter. If we used 5W-30 for example, the “5” and “30” actually measure the thickness, or viscosity, of the oil at different temperatures.

If an oil bottle has “5W30” on it, the oil will have a viscosity of a “5” weight oil when cold and a viscosity of a “30” weight oil when hot. This combination provides an oil that flows well at low temperatures, but still protects the engine at high temperatures. For comparison’s sake, SAE 5W-30 and SAE 0W-30 will flow better at even lower temperatures than 10W-30, while still providing protection at high temperatures. Just remember, the “W” stands for winter.[i]

Most cars today use either 5W-20 or 5W-30, regardless of geographic location. The brand you choose is up to you. Contrary to what your grandfather told you, it’s okay to switch brands.

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Posted in Car Advice