"Also, our good old standby of Mobil 1 15w50 has been reformulated to and SM classification, and now has 0.10% or less Zn and P. It looks like we will all need GM EOS pretty soon. (Thanks to John Dilger of the 911S Registry for letting me know of this sudden change on Mobil's part)"
"Same goes with Mobil 1 15w50 - if that is what you use, get a bunch of the SL formulation before all that is available is the new SM. You do not need the STP 4 cyl treatment or EOS with the old formulation of Rotella or Mobil 1, only the new ones."
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Charles Navarro
LN Engineering
http://www.LNengineering.com
Aircooled Precision Performance
'91 964 C4 Cab
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