Cummins 6C8.3/6L8.9 Air Compressor 3972531 Parts Catalogue Ref No. Part Name Part No. Required 1 Air Compressor 3972531 1 Above is the introduction of the Cummins 3972531 Air Compressor, while if you need any other Cummins spare parts or complete Cummins engine, Please further consult our sales.