Originally Posted by MINICooperL

I am about to buy oil for my first DIY oil change. Candidates on the list are:

1. Castrol Edge 0W-30 European Formula

Notes: If I choose this, I must buy it very soon since it is on sale this month.

Advantages:
A. I like the -30 weight part. During the warm up process, it is transforming from an oil with 0 weight to 30. I tend to think that a lighter weight oil is better during the warm up period.
B. Rumors about it being a Group IV PAO, not a blended III/IV which some accuse Mobil 1 and BMW High Performance of being.

2. Mobil 1 0W-40
Advantages:
A. Easily available from multiple sources. Castrol's 0W-30 is not easily available. If one store drops it, that leaves one. If that one drops it, then I need to find a new oil and fret over what to do with the remaining 2-3 qt. that I might have.
B. It's decent stuff, nothing to be ashamed of.

3. BMW High Performance 5W-30
Advantages:
A. None. I don't like the 5W part. I am suspicious that it's a variation of Castrol Softec TXT, which is not that great an oil

I am not considering some European brands that are rare and hard to find, such as Total, Motul, etc. Some of those oils are available for double the price.

In terms of viscosity, Mobil 1 is a lighter 40 weight and Castrol is a heavier 30 weight.

Castrol is generally about 80 cents more per quart even on sale at one store and $1.50 at the other. From a bean counter's standpoint, I don't think it's worth it. From an emotional standpoint, maybe.

Mobil 1 recommends using oil within 5 years so what I think I'll do is to see if Castrol is available and, if so, buy 3 years worth of it (assumes it was made a year ago and the year 3 oil change will last almost a year, which makes it 5). Then, if I have to change brands, at least I stuck with one for 3 years.