GMW17839

Description / Abstract: Introduction

Note: Nothing in this standard supercedes applicable laws and regulations.

Note: In the event of conflict between the English and domestic language, the English language shall take precedence.

Note: The words must, shall or will as used in this document mean a mandatory requirement.

Purpose. This test is designed to examine the life of coolant pump mechanical face seals when subjected to temperature cycling, varying inlet/outlet pressures and varying shaft speeds.

Applicability. This test is suited to the evaluation of all passenger car and light/medium duty truck mechanical face seals.

Design has a significant influence on test results. The largest GM designed pump currently in production on the Large Gas Engine (LGE) was used in the development of this diurnal test cycle. This test is to be used on components and coolant pump assemblies to identify and eliminate poor mechanical seal designs and/or materials. It can serve as a development, validation, or benchmark test. The water pump assembly, including gasket/seal, fasteners and structural interfaces is cycled on a thermal and rotational schedule while coolant is circulated internally.

Changes over time in the size of the largest mechanical seal water pump will require a change in 24 h Appendix B schedule. This will be reviewed no later than every five (5) year refresh of the document content.

Remarks.

Functional evaluation of external water pump assemblies to the engine gaskets (e.g., water pump cover or water pump to head or block) are subjected to GMW3155 leak test performance and are not part of this test evaluation.

This durability procedure, using two worst case pumps, evaluates the endurance requirements of coolant pump seals. The test sequence has a range of speeds,

Criteria. Validation requires completion of the test schedules described herein without exceeding the cumulative limit of 100 ml of vapor and liquid leakage (as defined in Section 5: Performance Criteria).

Part Conditions Requiring Retest. Design changes requiring complete re-validation include, but are not limited to:

• Changes in the seal ring or mating ring material,

• The seal production process,

• The specification of the installed height, or

• The interference fit

End of Test Criteria. Following completion of the durability test, the measurements and inspection outlined in 5.3 shall be completed and the results documented in a report.