Synthetic motor oil "group" categories

General Discussion
1

I see reference to various groups of 1-5 in regards to synthetic motor oils. It looks like most of them being sold today are Group 3 (cheaper ones), 4, or 5. I always see people saying that the Group 4 is better than 3 but what about 5? Is this a situation where 5 is better than 4 or would 4 be considered the best overall synthetic oil? I am not sure if this is a situation where a higher number is better or if the higher number is just a different category. I know that some of these synthetics are created from animal/vegetable oils while others are refined petroleum oil.

The reason I ask is because I understand many of the Group 3 synthetic oils would not meet the definition of a synthetic oil in Europe and that oils sold for European vehicles tend to have a higher concentration of Group 4 oils.

I have been told the cheapest Group 4 oil is the Mobil 1 0W40 synthetic which is commonly found for very low prices at Wal-Mart and parts stores when it is usually on sale with a filter included.

2

Time for a visit to bobistheoilguy.com. But unless you have one of the cars with non-standard synthetic oil grade specs (VW, BMW, and some GM, for example), it’s not something I’d spend much time worrying about…

3

Shelf Space…It’s getting to where you need an airplane hanger to store and display all the products called “Motor Oil”…

4

I remember using the old cardboard oil cans, I recall using Sears brand oil and Co-op dual season motor oil. This was in the 80’s. There wasn’t even a weight listed on the coop brand.v

5

Here is another question. If you want the best oil money can buy, do you want a group 4 or a group 5 oil? I am not sure which is better. I understand that group 4 oils are specified for some of the most expensive cars on the road but am curious about if group 5 is even better or the higher number just represents a different category of oil.