Many car handbooks advise use of very specific oils to use that are certified to meet manufacturer specification.
What is the consequence of using the same weight/viscosity/type oil (e.g. "5w30 fully synthetic") without the manufacturer spec (e.g. "5w30 fully synthetic meeting vw 505 01")?
I imagine with a new car it may affect manufacturer warranty but for older vehicles will it matter? If oil is topped up with the unbadged version when other oil is not available, is an oil change needed as soon as possible or can it wait?
(If the type of car matters, in our case we run a 2007 octavia diesel without dpf, though this would be a more useful q/a if it can be kept more general)