Thermostat 4133L509, 4225397M1 Perkins

The Perkins 4133L509 / 4225397M1 Thermostat Assembly is a genuine AGCO cooling system component engineered for Perkins 1100 Series diesel engines. Designed as an integrated thermostat and water outlet housing assembly, this OEM unit regulates engine operating temperature by controlling coolant circulation between the engine block and radiator system. The assembly combines a precision-calibrated thermostat element with a heavy-duty cast metal housing, creating a compact and leak-resistant cooling solution. During cold starts, the thermostat restricts coolant flow to help the engine reach operating temperature quickly, improving combustion efficiency, reducing engine wear, and supporting lower fuel consumption. As engine temperature rises, the thermostat progressively opens to allow full coolant circulation, protecting the engine against overheating under demanding working conditions. Manufactured from high-strength aluminum alloy with corrosion-resistant internal components, the Perkins 4133L509 thermostat assembly is built to withstand constant thermal cycling, coolant pressure, vibration, and harsh industrial environments. Its machined mating surfaces ensure accurate fitment and reliable sealing performance against coolant leakage. This genuine AGCO / Perkins thermostat housing assembly is widely used in Perkins 1100 Series 3-cylinder and 4-cylinder diesel engines commonly found in agricultural tractors, telehandlers, generators, construction machinery, and industrial equipment. Designed to OEM specifications, it delivers dependable cooling performance, long service life, and direct replacement compatibility.