sjanes

The symbol on the back of the container will say either "API SL" (old stuff) or "API SM" (new stuff). At least that's the way it's displayed here in Canada.

ltc

OK, so if I have this straight....

The 'original' Mobil 1 15W-50, fully synthetic, yadayada, had a RED cap....the oil I've always used in the 964 and is currently stored in the basement after cleaning out WalMart a while back.

The 'newest' Mobil 1 15W-50 has a silver cap and is as good as the original red cap. It is SM/SL rated.
http://www.mobil1.com/USA-English/Mo...1_15W-50_.aspx

The 'other' Mobil 1 (extended performance)15-50W has a gold cap, is SL rated and is NOT the stuff to use as it's SM rated.
http://www.mobil1.com/USA-English/Mo...ce_15W-50.aspx

OK, I surrender.

sjanes

I'm still confused myself. In the Canadian market, it appears they pulled the 15W50 in favor of the 5W50 around the same time this change was made.

For more info see:
https://rennlist.com/forums/showthre...ight=EOS+15W50
http://forums.pelicanparts.com/showt...0&pagenumber=1

chrisp

to add to the confusion they are reintroducing Mobil1 15-50 with higher ZDDP levels.

http://www.mobil1.com/USA-English/Mo...AQs.aspx#FAQs3

ltc

"This is a new Mobil 1 15W-50 formulation and is not the same as the product that was marketed a few years ago."

So, the simplest thing to do is just rebuild your engine rather than change the oil.