It has long been recognized that the diversity of specifications for Automotive Greases, established by the Original Equipment Manufacturer (OEM), have made it difficult, if not impossible, for the marketer of lubricating greases to make available all the many specified products. With the issuance of specification ASTM D 4950 Standard Classification and Specification for Automotive Service Grease, it has become possible to offer the products needed to provide proper service of automotive equipment. This ASTM specification includes two Performance Groups: chassis lubricants (letter designation L) and wheel bearing lubricants (letter designation G). Performance categories within these Groups result in two letter designations for chassis greases (LA and LB), and three for wheel bearing greases (GA, GB, and GC). The automotive industry is in general agreement that the highest performance category in each group (LB and GC) is suitable for service lubrication.
The NLGI has developed an identifying symbol, i.e., the NLGI Certification Mark. The OEM's Owner's Manuals, which illustrate this Mark, advise users to use only those greases that incorporate the Mark into their product label.
Since only the highest performance categories are acceptable to OEM, only categories LB and GC will be authorized for use with the Mark. The three versions of the Mark are shown in the illustration.
| Fig. 1: The NLGI identification symbols
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