Derale Inline Fluid Thermostat 13021 -6AN Fittings, Opens 180°F, Brass 3/8in Hose Barbs

Derale 13021 is an in-line fluid thermostat with -6AN fittings that opens at 180°F and closes at 165°F to regulate coolant or oil flow in performance systems.

This compact, ready-to-install thermostat from Derale provides a reliable temperature-triggered flow path for oil or coolant lines. Designed for inline mounting with -6AN ports and supplied brass 3/8" hose barb fittings, it helps control when fluid is routed through add-on coolers or bypass circuits. The unit is preset at the factory for consistent operation without adjustment, making it suitable for performance and retrofit applications where precise activation and durable construction are needed.

How does this thermostat control fluid flow in a cooling or oil system?

The Derale 13021 opens at 180°F, allowing fluid to pass through a cooling circuit, and closes at 165°F to stop flow when temperature drops. Because it’s in-line, it replaces a section of hose and reacts directly to the fluid temperature inside the line.

• Preset open temperature: 180°F (no user calibration required)
• Preset close temperature: 165°F for stable shutoff
• -6AN inlet and outlet ports for secure fittings
• Brass 3/8" hose barb adapters included for hose connections

What fittings and installation options are supported?

This thermostat is built with -6AN female ports and ships with brass 3/8" hose barb fittings so it can be adapted to AN lines or standard rubber hose. Its compact inline form factor makes it easy to mount in tight engine bays or near aftermarket coolers.

• -6AN inlet and outlet accept AN hose ends and adapters
• Included 3/8" brass hose barbs allow direct hose attachment
• Inline mounting reduces plumbing rerouting during installation
• Suitable for oil or coolant lines where -6AN is standard

Will this thermostat work for my application and what should I check?

Match the Derale 13021 to systems using -6AN lines or those that can accept the included 3/8" hose barb fittings. Verify the 180°F open / 165°F close range fits your desired operating window and ensure flow direction and mounting orientation are compatible with your plumbing layout.

• Confirm fluid type (oil or coolant) and compatibility
• Check line size: -6AN or 3/8" hose using supplied barbs
• Ensure the 180°F activation suits your cooling strategy
• Allow enough clearance for inline installation and hose routing

How durable and maintenance-friendly is the Derale 13021?

Constructed for performance environments, the thermostat uses robust internal components and brass adapters that resist corrosion while remaining serviceable. Being preset at the factory reduces the need for routine adjustments—periodic inspection for leaks and secure fittings is recommended.

• Preset mechanism reduces adjustment needs
• Brass fittings resist corrosion and provide reliable sealing
• Inline design simplifies swapping or replacement if required
• Inspect hoses and connections periodically for integrity

Who is this for: The Derale 13021 is aimed at DIY mechanics, performance vehicle builders, and retrofitters who need a compact, factory-preset inline thermostat to control coolant or oil flow. It’s well suited for setups using -6AN plumbing or 3/8" hose, and for anyone who wants an easy-to-install temperature-actuated valve to manage auxiliary coolers or bypass circuits without fine tuning.