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Automotive water pump seals which have failed prematurely during in-service use have been characterized using a variety of analytical methods. Nearly one hundred failed seals collected over the past several years from local automotive dealerships, major automotive manufacturers, coolant related fleet tests, and pump seal manufacturers have been examined as part of this study. This has enabled us to determine the chemical composition and morphology of surface deposits on failed seals and classify their failure mode. The main failure mode found for domestic in-service automobiles is filming, a term used to describe a failure type in which deposits form between the sealing surfaces resulting in a leak path. This paper reports on the composition, morphology and possible causes of in-service filming failures. In addition, the results of this study will be contrasted with those reported in other studies which found film transfer as the main type of failure.

Polyalkylene glycol (PAG) lubricants have been chosen for use with refrigerant HFC-134a by the mobile air conditioning industry. As this industry gears up to use PAG lubricants, several issues have surfaced regarding the handling of these products. Information will be presented regarding the hygroscopicity and elastomer compatibility of PAG lubricants. Polyalkylene glycols are being evaluated by the automotive industry as retrofit lubricants. PAG lubricants exhibit good stability in the presence of residual CFC-12. Data from retrofit tests performed on compressor test stands will be summarized. This paper will also describe the retrofitting of CFC-12 vehicles to HFC-134a and PAG lubricants.

Testing of nonasbestos gasket facing materials using high-temperature creep, high-pressure sealability, and an elevated pressure thermal conductance apparatus is presented. A discussion of the composition of nonasbestos facing suggests that thermal gravimetric analysis yields little useful information to the designer and that high-performance testing under thermal and/or compressive load are required. Materials are ranked in order of service temperature from cellulose fiber reinforced to homogenous flexible graphite. The data lead to the conclusion that the changes occurring in a gasket facing from ten percent thermally induced compressive creep can result in orders of magnitude change in sealability.