I have a question regarding oil changes and top up. For oil top up, I have purchased Castrol GTX oil. I know most dealers use bulk oil for oil changes, are we defeating the purpose of buying good oil for top up? Or do people bring their own oil or ask for a specific grade/brand at oil change and pay the difference.

Thanks.

 

When I did my oilchange at the dealer, they used the bulk oil (which was Motorcraft Syntec Blend 5W20).. (recommended by Ford).... So I went ahead and requested for extra bottles so I can top it off with the same kind of oil when needed......

Also they had Mazda Brand, etc.... I guess you can request for whatever brand you want, and If they don't have it, you could bring your own......
Just ask them what kind of oil they use for bulk oil.......
As for the mix, it is probably not worth to buy higher quality oil to top it off every now and then if the oil for the oil change was a lower grade...