1 Scope.

This document covers the requirements of rubber (55 to 80 hardness) used for fastener Isolator grommets. Test requirements for approved compounds are intended to permit usage in the de scribed temperature and engine fluid exposure environments. Currently only Class B compounds are defined. Silicone (VMQ) grommets not meeting Table 1 volatility limits can't be used in internal, direct oil exposed applications (e.g. PCV vent grommets or center bolt grommets on engine covers). These compounds will be designated with a grade 1 restriction (see 7.1). For all other grommets, see GM221M.