1137700700 Original Excavator Thermostat for ISUZU 6BG1 Engine

The original thermostat part number 1137700700 (also written as 1-13770070-0) is the core temperature control component of the cooling system for the ISUZU 6BG1 series diesel engines (displacement 5.6L, power 105-130kW). This thermostat is mainly suitable for medium-sized excavators from brands such as Hitachi, Sumitomo, and Shengang equipped with 6BG1 engines, such as Hitachi EX200-5, ZX200-3, ZX210-3, Sumitomo SH200-5, SH240-5, and Shengang SK200-8. Its common models are often labeled as 6BG1 and 6BD1 series, belonging to the wax thermostat. It is usually installed at the inlet of the engine water pump or inside the thermostat housing, and is used to automatically switch between small cycle (fast warm-up) and large cycle (efficient heat dissipation) according to the coolant temperature, ensuring that the engine operates in the optimal temperature range of 80-95 ℃.

This product is an original wax thermostat, and its core temperature sensing element is a sealed paraffin capsule. When the coolant temperature reaches 76-80 ℃, the paraffin expands due to heat, pushing the main valve to start opening; When the temperature rises to 90 ℃, the valve is fully opened (lift ≥ 8mm), and the coolant flows through the radiator for a large circulation. The shell is made of brass or aluminum alloy casting, the valve is made of stainless steel or galvanized steel material, and the seal is made of high temperature resistant rubber, which can withstand engine high temperature (up to 120 ℃), high pressure (up to 3bar) and coolant corrosion. As an original component, its opening temperature, response speed, and sealing performance are strictly matched with the cooling system of the ISUZU 6BG1 engine, effectively balancing the engine's thermal efficiency, emission control, and mechanical wear.

It is recommended to observe whether the dashboard water temperature gauge stabilizes at 80-95 ℃ after warming up every 500 working hours; Check for coolant leakage or rust on the thermostat housing. Fault diagnosis: If the engine warms up slowly and the water temperature is too low, it may be a normally open thermostat fault; If the water temperature rapidly rises to boiling point, it may be a normally closed fault. Remove the thermostat and place it in hot water above 90 ℃ for testing: normally, the valve should be fully opened, and after cooling, it should be completely closed. Key points for replacement: Before replacement, turn off the engine and cool it down, and drain the cooling system; Use a dedicated sleeve during disassembly to avoid damaging the shell; Before installing a new thermostat, make sure that the exhaust hole (if any) is facing upwards, and apply a small amount of sealant to the sealing gasket. Tighten it to a torque of 15-25N · m; After installation, it is necessary to add the original designated model of coolant, start the engine to exhaust the air, and observe whether the water temperature changes and the temperature difference between the radiator inlet and outlet pipes are normal. Preventive maintenance: It is recommended to check or replace the thermostat during engine overhaul every 8000-10000 hours, and always use original parts to ensure temperature control accuracy and system reliability.