82℃ 180℉ Thermostat 3335550 4973373 for Cummins ISX QSX 4318197 Engine

Thermostat for Cummins ISX QSX

This 82℃ (180℉) thermostat regulates engine coolant temperature for Cummins ISX and QSX engines, matching OEM reference numbers 3335550, 4973373, and 4318197. It opens at the rated temperature to maintain optimal operating conditions and prevent overheating.

Overview

This thermostat is a direct replacement for Cummins heavy-duty engines, controlling coolant flow to keep the engine within its ideal temperature window. It fits Cummins ISX and QSX series, ensuring consistent thermal management under load. With a precise opening point of 82℃ or 180℉, it supports reliable cold starts and efficient high-temperature operation.

Built For Performance

• Opens at 82℃ (180℉) for precise temperature control
• Durable wax-pellet element provides consistent response
• Stainless steel frame resists corrosion in coolant systems
• Rubber seal ensures leak-free seating in the housing
• Direct replacement for OEM 3335550, 4973373, 4318197

Fits These Machines

• for Cummins ISX engines
• for Cummins QSX engines

On-The-Job Use

• Replaces a stuck-open or stuck-closed thermostat during cooling system service
• Supports highway trucking, construction, and agricultural applications
• Ensures proper warm-up in cold climates for ISX and QSX engines
• Used at scheduled maintenance intervals for severe-duty fleets

Specs At A Glance

Good To Know

Q: Is this thermostat a direct OEM replacement? A: Yes, it matches the 3335550, 4973373, and 4318197 cross-reference numbers, designed to fit Cummins ISX and QSX engine cooling systems.

Q: What happens if my thermostat is stuck closed? A: A stuck-closed thermostat can cause the engine to overheat quickly, since coolant cannot pass to the radiator. Replacing it with this unit restores proper heat dissipation.

Slight variation in finish or dimensions may occur between production runs, and fit can depend on serial number, so confirm compatibility before ordering.