OTTO Excavator Parts Nkr77 4Jh1 Cooling Water Bypass Pipe 8972399790 897239-9790 8-97239979-0 For Isuzu Durable 8-97239979-0 pipe fits OTTO Nkr77 & Isuzu 4Jh1. Resists mining dust/heat, pressure-stable. Ensures steady engine cooling for non-stop heavy work.