Replacement Thermostat

The Painless Wiring replacement thermostat (model 30111) is a precision engine temperature control component engineered for custom automotive builds and cooling system upgrades. This electric temperature switch activates at 185 degrees Fahrenheit and deactivates at 175 degrees, providing tight hysteresis control critical for fuel injection systems, custom radiator setups, and engine swap projects. Whether you're installing a modern cooling module in a classic car or fine-tuning a modified engine's thermal management, this replacement thermostat delivers the reliable switching accuracy that professional builders and serious enthusiasts demand.

Built by Painless Wiring—a trusted name in automotive electrical solutions—this unit features a 3/8 inch NPT (National Pipe Taper) threaded port for seamless integration into existing cooling passages and aftermarket radiator systems. The 185/175-degree setpoint is ideal for EFI conversions and modern engine management systems that require precise coolant temperature signaling to optimize fan operation and fuel mapping. The compact form factor (2.7 x 1.45 x 4 inches) and lightweight construction (0.2 lbs) minimize installation complexity while maintaining robust electrical contacts and reliable switching cycles over extended use.

This replacement thermostat is ideal for builders upgrading cooling systems, EFI tuners, and mechanics servicing late-model engine swaps where OEM thermostat housings have been modified or eliminated. The NPT port threads directly into most custom radiators and water-neck adapters without additional fittings. If your engine is running hotter than desired, your fan clutch engages erratically, or you're switching to a modern fuel-injection setup, this Painless Wiring unit ensures consistent thermal control and accurate engine management feedback across all driving conditions.