API Service level Timeline?

Messages
8,626
Location
Champlain/Hudson Valley
Hello, I unearthed an old bottle of 10W-30 motor oil from Big A Auto Parts had an "API SH" service level on the label. I was wondering if ever there's been a time line for those levels. I was 15 when Quaker State introduced SD with their DeLuxe oils. CHEERS, Kira
 
Messages
15,128
Location
Canada
Yeah, every API service rating has a certain time associated with it. Very roughly, they are something like: SE: 1971-1981 SF: 1981-1987 SG: 1987-1992 SH: 1992-1997 SJ: 1997-1999 SL: 1999-2004 SM: 2004-2010 So, the oil bottle you have is from the mid-1990's, basically.
 
Messages
777
Location
Herndon, VA
If I am not mistaken, SD was equivalent to the older "MS" (Motor Severe) rating. I vaguely recall that when the new API service ratings for gasoline engines was introduced (Sx ratings) that "SD" corresponded to an equal level of performance by the old "MS" rating, and that "SE" was introduced at the same time to indicate a level of performance above and beyond the old "MS" rating. Can someone with a better memory confirm or correct this?
 
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