8981566480 Original Excavator Water Temperature Sensor for ISUZU 4HK1 Engine

The original water temperature sensor part number 8981566480 (also written as 8-98156648-0) is the core monitoring component of the cooling system for the ISUZU 4HK1 series diesel engines (displacement 5.2L, power 129-157kW). This sensor is mainly suitable for medium-sized excavators from brands such as Hitachi, Sumitomo, and Shengang equipped with 4HK1 engines, such as Hitachi ZAX240-3, ZX200-3, ZX210-3, Sumitomo SH240-5, SH350-5, and Shengang SK200-8, SK250-8, etc. Its common models are often labeled as 4HK1 and 6HK1 series, belonging to the dual wire thermistor type water temperature sensor. It is usually installed near the engine thermostat housing or cylinder head water jacket, and is used to provide accurate temperature signals to the ECU to control fuel injection quantity, ignition advance angle, and fan start stop.

This product is an original water temperature sensor that uses a negative temperature coefficient (NTC) thermistor as the sensing element. Its resistance value decreases with increasing temperature (typical range: about 48k Ω at -40 ℃ and about 191 Ω at 100 ℃). The sensor housing is made of brass or galvanized steel material, filled with high-temperature resistant sealant, and has IP67 dust and waterproof performance. It can withstand harsh working conditions such as engine high temperature (up to 150 ℃), high pressure (up to 3bar), and continuous vibration. Its electrical interface is a 2-pin waterproof plug, which outputs 0.5-4.5V analog voltage signals and is perfectly matched with the ECU of the ISUZU 4HK1 engine, ensuring temperature monitoring accuracy and response speed under cold start, warm-up, and high load conditions.

Suggest checking the sensor harness plug for looseness and oxidation every 500 working hours; Whether there is coolant leakage or corrosion in the shell; Is there any abnormal fluctuation in the reading of the dashboard water temperature gauge. Fault diagnosis: If there is difficulty starting the engine cold, unstable idle, increased fuel consumption, or the dashboard water temperature warning light is constantly on, a multimeter can be used to measure the sensor resistance value (normally about 2.6k Ω at 20 ℃, and the resistance should continuously decrease as the temperature increases); The diagnostic instrument can also be used to read the water temperature data stream in the ECU and compare it with the actual temperature. Key points for replacement: Before replacement, turn off the engine and cool it down, slowly release the cooling system pressure; Use a 19mm deep sleeve to apply vertical force during disassembly to avoid damaging the threads; Apply a small amount of sealant to the threaded part before installing the new sensor, and tighten it with a torque of 15-25N · m; After installation, it is necessary to replenish the original designated model of coolant and start the engine to exhaust the air. Observe whether the instrument display and fan work properly. Preventive maintenance: It is recommended to check or replace sensors during engine overhaul every 8000-10000 hours, and always use original parts to ensure monitoring accuracy and system reliability.