Dear Car Talk:
My reason for writing is that all these alphanumeric algorithmic specifications on oil these days are confusing me. I have a 2009 Jaguar XF with a 4.2-liter engine. I've owned many older Jags, but this is the first one that states I need WSS M2C913-B, which I learned is a Ford part number. But I can't find it anywhere. What oil would be safe to use in this car now?
Well, you've fallen into an unusual automotive black hole, Michael.
Ford owned Jaguar until 2008. Then the great recession hit, and Ford sold everything it could spare except old pairs of Henry Ford's boxer shorts. So the 2009 Jaguars were basically designed by Ford but sold by Jaguar (which was, by then, owned by the Indian conglomerate Tata).
So if you ask Jaguar for part number WSS M2C913-B, they'll tell you to go ask Ford. And if you ask Ford, they'll tell you that the 2009 Jaguar is not their problem, go ask Jaguar.
But not to worry, Michael. WSS M2C913-B is actually a Ford of Europe part number, which is why you can't find it at your local Ford dealership.
The best I can tell, it's basically a fully synthetic 5W-30 oil. And since oil specifications tend to improve over time, I think you're completely safe using any of the brand-name synthetic oils available here in the States. So a 5W-30 version of Castrol Edge or Mobil 1, to cite two examples, should be entirely safe for your Jaguar.
And it should be cheaper than flying to England once a year and coming back with a case of WSS M2C913-B in the overhead bin.