Oil Number - Pontiac 1953 Owner's Manual

eNgiNe /!'lIbricatioN
The tenus Regular, Premium and Heavy Duty have generally been
used to designate the types of engine oils supplied by the oil industry
to meet the requirements of various service conditions. These terms
are being replaced by the designations "For Service ML", "For
Service MM", and "For Service MS or DG".
Under average driving conditions, petroleum based engine oils of any
of these types, as supplied by reputable marketers, should be satis-
factory for use in Pontiac engines .
. Under driving conditions where the engine is required to develop
nearly full power for a large percentage of time, as in sustained high
speed driving, it may be desirable to use oils which have been desig-
nated as "Premium" or "Heavy Duty" and which now may be
designated as "For Service MM" or "For Service MS or DG".
S.A.E.
OIL
NUMBER SYSTEM-The oil numbering system
adopted by the Society of Automotive Engineers classifies lubricants
according to fluidity or viscosity, and has no reference to any other
characteristic or property. The oils with the lower numbers are
lighter al1d flow more readily than do the oils with the higher numbers.
The letter "W" after the number indicates an oil adapted for cold
weather starting.
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