For contact information, visit www.improvedracing.comCopyright © 2008-2016 Improved Racing Products, LLC. All rights reserved.

Rev 160323

High Flow Remote Oil Thermostat 165°F

Part No. FSM-165

Made in USA

Important: Read these instructions in their entirety prior to installation.

For contact information, visit www.improvedracing.comCopyright © 2008-2016 Improved Racing Products, LLC. All rights reserved.2

Application Notes

• The FSM series thermostat is designed for universal oil temperature control in engines, transmissions, differentials, and industrial cooling applications.

• Accelerates warm-up and prevents over-cooling.• Under no circumstances can the thermostat fail in such a way that oil

flow to the engine or heat source is blocked.• Thermostat is re-buildable. Should the unit fail, it can be shipped

back to Improved Racing for a rebuild with a new thermal element and seals.

• Not recommended for use with highly corrosive fluids.

TechnicalSpecificationsStabilization Temperature 167°F +/- 2°F (75°C +/- 1°C)Activation Temperature 160°F +/- 2°F (71°C +/- 1°C)Max Operating Temperature 302°F (150°C)Min Operating Temperature -22°F (-30°C)Max Recommended Pressure 200 psi (13.79 bar)Dimensions (W x H x D) 3.2” x 2.0” x 2.0” (8.13 x 5.08 x 5.08 cm)Weight (no brackets or fittings) 12.7 oz (360 g)Housing Material 6061-T6 billet machined aluminumHousing Finish MIL-A-8625 Type II anodizing, blackValve Material 6061-T6 billet machined aluminumValve Finish PlainSpring Material 316 stainless steelSpring Finish Ultrasonic citric acid passivationThermal Actuator Material Brass and zinc-plated steelPorts -10AN SAE J1926-1 / MS16142 O-ring boss Estimated Service Life > 5,000 heat cycles

Operation

The thermostat bypasses the oil cooler until the fluid reaches the activation temperature. At the activation temperature, the bypass valve begins to close, forcing oil through the cooler and allowing it to cool. If the cooler’s cooling capacity is sufficient, the fluid will tend to stabilize at the rated stabilization temperature.

For contact information, visit www.improvedracing.comCopyright © 2008-2016 Improved Racing Products, LLC. All rights reserved. 3

Parts List

• FSM thermostat (1)• Mounting brackets for up to 1/4” (6mm) screws (2)• Bracket retaining screws, M4 x 0.7mm (4)• AN adapter fittings (optional) (4)

FlowConfigurations

1. The recommended standard configuration (Figure 2) provides faster warm-up times.

2. The reverse configuration (Figure 3) will result in slower warm-up times.

3. The cross flow configuration (Figure 4) provides quick warm-up times like the standard configuration and may be a more convenient hose routing arrangement in certain applications.

Oil from coolerTo cooler

To engine or transmission

Bypass valve closes, forcing 100% of oil flow through the oil cooler. If oil temps drop, the bypass valve opens to prevent over-cooling.

Oil from engine or transmission

To engine or transmission

Oil from engine or transmission

Oil from coolerTo cooler

Over 90% of oil flow is returned to the engine through the bypass valve to accelerate engine warm up and prevent over-cooling.

Less than 10% of oil flow circulates through cooler to prevent air pockets and shocking the system with cold oil.

Figure1-ThermostatOperationDiagram

For contact information, visit www.improvedracing.comCopyright © 2008-2016 Improved Racing Products, LLC. All rights reserved.4

InstallationInstructions

1. Select a flow configuration and assemble oil lines to suit. The standard flow configuration is recommended.

2. Fill the oil cooler with oil prior to connecting the lines. Screw the AN adapter fittings to the thermostat housing, then connect the oil lines.

FROMENGINE

TOCOOLER

TO ENGINE

FROMCOOLER

FSM-185185°F THERMOSTAT

MADE IN USA 140528

Figure2-Standard Flow

FROMENGINE

TOCOOLER

TO ENGINE

FROMCOOLER

FSM-185185°F THERMOSTAT

MADE IN USA 140528

Figure3-Reverse Flow

FROMENGINE

TOCOOLER

TO ENGINE

FROMCOOLER

FSM-185185°F THERMOSTAT

MADE IN USA 140528

Figure4-Cross Flow

For contact information, visit www.improvedracing.comCopyright © 2008-2016 Improved Racing Products, LLC. All rights reserved. 5

3. Tighten all fittings. Do not overtighten. Aluminum fittings are prone to damage and

leaking if overtightened.4. Check and top off the engine’s oil level.5. Remove the fuel pump fuse and crank the engine over for several

seconds to build oil pressure and prime the lines with oil.6. Replace the fuel pump fuse, then start the engine.7. Check for leaks and adjust or tighten fittings if necessary.8. Shut off the engine and top off the engine’s oil level once again.9. Congratulations! Installation is now complete.

Thank you for purchasing an Improved Racing product!