I was at a local auto parts store and saw all castrol motor oil are on sale, 50% off to be exact, and decided to grab 3 jugs. I checked the castrol website and found this to be the oil for our cars CASTROL EDGE FTT A3/B4 0W-30 so that is what I grabbed. Now upon getting back home I checked the mini oil that I was purchasing from the dealer and saw it as A5/B5 0W-30. So I am wondering if it is safe to mix those two together as I will be using the A3/B4 as fill ups in-between oil change or a bad idea.

I let the dealer change the oil for me as I only pay $69+tax for it plus I get unlimited starbucks hot coffee/hot chocolate and some treats while waiting for them to finish it. So doing DYI is not even an option if it is that cheap.

 

I'm not up on the A / B codes, or what you told the dealer when you bought your oil. However, it's a bad idea to mix oil types. If you have a turbo, there's a specific oil for it --- something like "sn/b2". Then there's synthetic vs non-synthetic --- never mix these. Ideal weight depends on geography, driving habits, and engine condition.

If you trust the dealer to be using the right stuff, try to exchange unused jugs for similar stuff at your local auto parts store.

 

Here's something to read about A3/B4 & A5/B5 differences

https://www.bobistheoilguy.com/forum...A3/B4_vs_A5/B5

https://www.bobistheoilguy.com/forum.../B5--2013_Mini

 

I have read those before I posted here. I am sure the oil I got will work with the justa but I want to know if I can mix A3/B4 with A5/B5 oil without asking for trouble,

 

If it is a car you intend to ride into the sunset with I would avoid mixing oil types. If it was my car, I wouldn't worry so much. When you let someone else do your oil you never really know what they are throwing in the car anyway. I've had oil changes done by "pro" BMW/MINI shop who put synthetic into a conventional oil car. That caused me lots of pain down the road.