Overview – THERMAL ELEMENT 3924388
Engineered for Cummins B, C and 855-family engine cooling systems, the Cummins THERMAL ELEMENT 3924388 meets the tolerances your equipment was designed around.
Parts Characteristics
A wax-pellet thermostat element that regulates coolant temperature by metering flow to the radiator. It begins opening at its calibrated temperature and reaches full travel a few degrees later, holding the engine in the window where combustion is efficient and oil stays protective.
Applicable Models & Applications
Used in Cummins cooling systems across industrial engine families. Confirm the calibrated opening temperature stamped on the element or listed in your parts book before ordering – the same engine family used different ratings across applications and climates.
Maintenance & Replacement
Watch the gauge behaviour on every start-up. An engine that takes forever to warm up, or one that wanders into the red under load while the radiator stays cool, is telling you the thermostat has stopped controlling. Confirm with the hoses: a cold top hose on a hot engine means the element never opened.
Replace the thermostat whenever the cooling system is serviced after an overheating event, and at the engine manual’s interval in high-hour machines. A thermostat is too cheap to diagnose to death – when in doubt, fit a new calibrated element and retest before condemning the water pump or radiator.
To fit a new element, drain coolant below the housing level, remove the housing, and note the element orientation and any jiggle pin position. Clean both gasket faces, fit the new element the same way round with a fresh gasket, torque the housing bolts evenly, then refill, bleed the system and confirm normal warm-up and stable temperature under load.
Never run the engine with the thermostat removed ‘to stop overheating’ – the coolant then flows too fast through the radiator to shed heat, and the engine swings between cold and hot. Match the rating in your parts book and keep a spare element in the service kit.
Price Reference (USD)
Expect a market price around USD 15-50 for the THERMAL ELEMENT 3924388; we confirm the exact figure on your pro-forma invoice.
Value & Service
We stock the common Cummins thermostat ratings brand-new and confirm the calibrated temperature against your engine model, so the cooling system is right the first time.
Racer Machinery’s catalog covers the full Cummins Engine Parts range, and the THERMAL ELEMENT 3924388 is priced to keep your maintenance budget under control.







