OTTO Excavator Parts Sh4503B 6Uz1 Thermostat Tube 8976037960 897603-7960 8-97603796-0 For Isuzu This OTTO excavator part (Sh4503B 6Uz1) is a thermostat tube (PN: 8976037960/897603-7960/8-97603796-0) designed for Isuzu engines. It regulates coolant flow to maintain optimal engine temperature in compatible excavator models.