GMNA GM209M PDF

This document covers the requirements of rubber (55 to 80 hardness) used for fastener isolator grom-mets. Test requirements for approved compounds are intended to permit usage in the described tem-perature and engine fluid exposure environment& Currently only Class B compounds are defined. Sili-cone (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 GM221 M.

Material Description. The term grommet — used in this document — is as defined by the GM Corporate Manual of Functional Names Glossary. It is an item of any peripheral shape having flanges or a groove(s) on its outer perimeter to provide a self-retaining characteristic when inserted in a hole. The grommet is designed to insulate or protect an item passing through it or used as a mount or seal for another part.

Table 1 (p. 6) contains requirements for all grommet compound& Specific applications are assigned a type based on nominal micro-hardness (International Rubber Hardness Degree). Table hardness will vary slightly as dictated by approved compounds. Type is subdivided into class (A-C) depending on the tem-perature and fluid resistance requirements. A spe-cial grade 1 restriction designation is applied solely to high (more than 1%) volatile silicone grommet com-pound(s).

The continuous functional temperature range is defined by ASTM D1329 TR10 and the upper tem-perature limit (CUTL) by SAE J2236.

Compound Nomenclature. Identify your type using ASTM D1418 or ISO 1629. 1.1.4 All Type 1, Class B materials are silicone (VMQ). Other materials may be used if the need arises.

All prints designating GM209M before January 2002 were Type 1 (class B) silicone compounds. Previous print references to Type 1A are now Type 2.

Symbol. The part molder shall identify the pro-duction material for recycling or disposal according to SAE J2332 or VDA 260.

For Example: Silicone >VMQ<

The part molder shall also be identified by the appro-priate rubber manufacturer's association (RMA) identification code, along with any additional engine group and component division requirements on the detail part or assembly drawing.

Typical Application.

Cam, rocker, front and rear cover M6 or M8 fastener grommets for vibration isolation.

Type 1, Class B: 4.3L fastener isolator grom-mets for engine cover (P/N 10201395); front timing cover (P/N 10213294) and rocker cover (P/N 10201396). Type 2, Class B: L6, 4.2L cam cover (P/N 24577570) and LHIILH2 cam cvr. bolt isolator (P/N 12573742). Type 3, Class B: 1.9L Saturn cam cover (P/N 21006030) and Gen IV valve rkr. cvr. (P/N 12559893).

Remarks. Approved compounds properties for each type of rubber are listed in Tables 2 through 4. The table values are a compilation of data from usu-ally no more than two compounds. Table values will change as the need for improved ranges are identi-fied. Previously approved compounds shall be re-moved when they can no longer meet the new range of table values.