185 Temp Switch for Use w/Alum Heads

The 185 Temp Switch for Use w/Alum Heads is a precision engine cooling control device engineered for automotive and marine applications requiring reliable thermostat operation. This two-wire temperature switch activates at 185 degrees and deactivates at 165 degrees, providing hysteresis that prevents relay chatter and ensures stable fan clutch or electric fan engagement. Designed specifically for vehicles equipped with aluminum cylinder heads, this switch integrates seamlessly into existing cooling systems where OEM or aftermarket thermostat housings accept 3/8 inch NPT threads.

Manufactured by SPAL Advanced Technologies, a leader in thermal management solutions, this temperature switch features a durable two-wire configuration that simplifies installation in single-fan or multi-fan setups. The 185-degree activation point is calibrated for engine blocks that run hotter under load or in high-ambient conditions, while the 165-degree cutoff prevents unnecessary cooling system cycling and reduces parasitic load on the engine. The aluminum head design ensures corrosion resistance and superior heat transfer, critical for accurate temperature sensing in direct-mount applications where coolant contact is continuous.

This switch is ideal for builders and technicians upgrading cooling capacity on naturally aspirated or turbocharged engines, as well as marine and industrial applications where precise coolant temperature control is non-negotiable. Installation requires only a 3/8 inch NPT port on the thermostat housing or coolant manifold; the compact form factor (3.1 × 1 × 7.95 inches) fits confined engine compartments with minimal clearance concerns. Verify your thermostat housing features the correct NPT thread size and that your electrical harness supports a simple two-wire switch configuration before ordering.