Mishimoto MMOP-EXTFC Universal Inline Oil Thermostat 185 DegF -10AN 6061 Aluminum

Vehicle Fitment

• Universal - suitable for any engine oil, transmission fluid, or driveline fluid cooling system where a thermostatic control unit is required in an -10AN line circuit. Compact design makes it ideal for custom builds and tight engine bay applications where a standard oil sandwich plate cannot be used. Some fabrication of oil lines and custom bracket mounting may be required.

Fitment Notes

• Universal fitment - this is a standalone inline thermostat unit, not a direct-fit kit for a specific vehicle. The installer is responsible for routing -10AN oil lines from the oil source to the thermostat inlets, and from the thermostat outlets to the external oil cooler or heat exchanger.
• Four M20 x 1.5 threaded ports accept -10AN fittings (included). Verify that your AN line and fitting sizes are compatible with -10AN before purchase.
• Default thermostat opens at 185°F (85°C). Optional replacement thermostats are available at 160°F (71°C) and 200°F (93°C) for applications requiring different operating temperature targets. Thermostats are user-serviceable and easily interchanged.
• Installation torque specification: 15-25 ft-lb (operating range) for all straight fittings and banjo bolts. Do not exceed 35 ft-lb maximum torque rating.
• Caution: It is the installer's responsibility to verify that all thermostat plugs, NPT plugs, line fittings, and connections are fully tightened before operating the vehicle. Mishimoto recommends checking all connections at regular intervals, especially during the first few miles after installation.

Features

• Precision in-line thermostatic oil plate CNC-machined from a single piece of billet 6061 aluminum - engineered to regulate engine oil, transmission fluid, or any driveline fluid in custom oil cooler circuits where space constraints prevent the use of a standard oil filter sandwich plate.
• Built-in wax-element thermostat opens at 185°F (85°C) to allow fluid flow to the external oil cooler - keeping the cooler bypassed during cold starts and warmup to protect the engine from over-cooled oil, then opening at operating temperature to route fluid through the cooler when thermal control is needed.
• Compact form factor (3.95" x 2.05" x 1.30" without fittings; 3.95" x 4.29" x 1.30" with fittings installed) makes this unit the ideal solution for tight engine bay packaging where a conventional sandwich plate cannot be accommodated due to clearance constraints from exhaust, accessories, or intake components.
• Thermostat unit is fully user-serviceable and can be removed and swapped in minutes - enabling the installer to change the activation temperature to 160°F (71°C) for track or high-performance applications, or 200°F (93°C) for applications targeting a higher operating threshold. Replacement thermostats are available separately.
• Four -10AN fittings with high-quality Dowty seals included - Dowty seals provide a reliable, leak-free metal-to-face seal at each fitting connection, eliminating the potential for weeping or seeping at the AN interfaces under oil pressure cycling.
• Included CNC-machined heat sink provides additional passive thermal dissipation at the thermostat body and provides a distinctive, purposeful aesthetic in the engine bay.
• Universal mounting bracket included for flexible positioning in any engine bay orientation or custom build application.
• Installation difficulty rated Easy. Backed by the Mishimoto Lifetime Warranty.

Specifications

• Type: In-line (remote) thermostatic oil plate
• Material: Billet 6061 aluminum, CNC-machined (single piece)
• Fluid Compatibility: Engine oil, transmission fluid, any driveline fluid
• Default Thermostat Opening Temperature: 185°F / 85°C
• Optional Thermostat Temperatures: 160°F (71°C), 200°F (93°C) - sold separately
• Port Thread Size: M20 x 1.5 (4 ports)
• Fitting Size: -10AN (2 inlets, 2 outlets)
• Fitting Seal Type: Dowty seals
• Overall Size (without fittings): 3.95 in x 2.05 in x 1.30 in
• Overall Size (with fittings): 3.95 in x 4.29 in x 1.30 in
• Fitting Torque: 15-25 ft-lb recommended; 35 ft-lb maximum

Included Components

• 1x Remote thermostatic oil plate (billet 6061 aluminum)
• 4x -10AN fittings with Dowty seals
• 1x CNC-machined heat sink
• 1x Built-in thermostat, 185°F / 85°C
• 1x Universal mounting bracket
• Necessary hardware
• Mishimoto Lifetime Warranty

Product Description

The Mishimoto MMOP-EXTFC is a universal in-line thermostatic oil plate CNC-machined from a single piece of billet 6061 aluminum, designed to provide thermostatic temperature regulation for engine oil, transmission fluid, or any other driveline fluid in custom-built oil cooling circuits. The unit was developed specifically for build scenarios where a standard oil filter sandwich plate cannot be used - tight engine bays, applications where the oil filter housing location doesn't allow for a sandwich plate, or custom fabrication projects where the oil cooling circuit is routed through -10AN lines rather than through the filter mount. Rather than requiring a large, fixed sandwich plate at the oil filter, this remote thermostat can be mounted anywhere in the -10AN oil line run using the included universal mounting bracket.

The thermostat function is identical to the one used in Mishimoto's sandwich plate lineup: a wax-element thermostat that remains closed below the activation temperature, keeping all oil flow bypassed directly back to the engine without routing through the cooler. Once oil temperature reaches 185°F (85°C), the thermostat opens and oil begins circulating through the external cooler. This behavior prevents over-cooling during cold starts and warmup - a common problem with non-thermostatic oil cooler circuits that can cause excessive oil viscosity at low temperatures, increased wear, and extended warmup times. When the target application requires a different operating temperature, the thermostat unit is user-serviceable and can be swapped with Mishimoto's optional 160°F (71°C) or 200°F (93°C) thermostat units to precisely match the thermal requirements of any build.

All four -10AN connections use Dowty seals - a high-quality metal-to-face sealing method that provides reliable, leak-free joints under oil pressure cycling, superior to simple AN o-ring or crush-washer connections in sustained high-pressure applications. The included CNC-machined heat sink adds passive thermal dissipation at the thermostat body and provides a purposeful aesthetic finish in any engine bay. Overall dimensions are 3.95" x 2.05" x 1.30" without fittings and 3.95" x 4.29" x 1.30" with fittings installed - compact enough to fit in tight underhood spaces. All fitting connections should be torqued to 15-25 ft-lb and verified before operation; check all connections during the first miles of operation after installation. Covered by the Mishimoto Lifetime Warranty.