3/8" NPT Thread-In Analog Fan Controller Thermostat

• Activates electric cooling fans at 185°F on, 165°F off for consistent fan control

• Thread-in design installs directly into the coolant stream — no housing needed

• Universal 3/8" NPT fit for custom cooling systems and compatible fan controllers

• Single male terminal for straightforward electric fan wiring connection

This thread-in fan controller switch activates electric cooling fans at a preset temperature range — turning fans on at 185°F and off at 165°F — for consistent electric fan operation in custom cooling systems. The 3/8" NPT thread-in design installs directly into a threaded port in the coolant stream, with a single male terminal for wiring to a compatible fan relay or controller.

This is a temperature-activated fan control switch, not a coolant-flow thermostat — it does not regulate coolant circulation through the engine. It's a universal-fit component sized to a 3/8" NPT threaded port rather than a specific vehicle or engine, commonly installed in a radiator, water neck, or block port with a matching thread size and adequate depth for accurate temperature sensing.

Use thread sealant (Teflon tape or pipe thread sealant) on installation — dry-fitting NPT threads can result in coolant leaks.

Installation Requirements
This switch requires adequate thread engagement into the coolant stream for an accurate temperature reading — confirm your radiator, water neck, or block port depth matches the sensor's threaded length before installing. Apply thread sealant to the 0.375" NPT threads, since NPT fittings installed dry commonly leak.

Wiring
The single male terminal connects to a compatible fan relay or controller wiring setup — this switch triggers fan activation but doesn't independently power the fan, so it needs to be wired into an existing or compatible electric fan control circuit.

Is this a coolant-flow thermostat or a fan switch?
This is an electric cooling fan switch, not a coolant-flow thermostat. It controls fan activation based on coolant temperature; a separate thermostat is required to regulate coolant flow through the engine.

What temperatures does this switch activate at?
The switch turns the fan on at 185°F and off at 165°F.

Will this fit my specific vehicle?
This is a universal-fit component with 3/8" NPT threads. Fitment depends on your radiator, water neck, intake, or engine having a compatible 3/8" NPT coolant port rather than on vehicle make or model.

Do I need thread sealant to install this?
Yes — use a coolant-compatible thread sealant suitable for NPT threads. Follow the manufacturer's installation instructions, particularly if the switch requires electrical grounding through its threaded body.

How do I know if my port is deep enough for accurate sensing?
Verify that the port provides adequate thread engagement and positions the sensing portion of the switch in the coolant flow without bottoming out or interfering with surrounding components.

Does this include the wiring or relay for my fan?
No — this switch has a single male electrical terminal for connection to a compatible fan control circuit. Any required wiring, relay, or controller must be sourced separately.