Really? I have 15W40 stamped onto the oil cap of my motor. But your more then likely right

People run different oils because although the engines the same the condition and location of them are different. And the people who service them have different thoughts.
I have no idea why my engine dosnt like 15w40 or even 15w50 but it loves 20w60.
Not that it matters a hell of alot.

Cant really see what the issue would be, not light stuff that we run in the jap cars. But having trouble trying to find Luca in this town, dont really want to add any other brand as its good oil!

hi all i have a 94 ef fairmont sedan and a 97 el fairmont wagon with over 350000 km on both of them. i was just wondering with oil ford recommends 15w-40 but i was told i can use 20w-50 because of age of cars and the amount of km's done. is this so and also mineral oil or synthetic. i do oil changes every 3 months as these are family cars and want to keep them running great for a few more years before having to get a new car with the kids growing. thanks in advance for all assistance.