Reische 170°F Performance Thermostat for Mustang 3.7 / 5.0 / 5.2

The Reische 170°F Performance Thermostat is designed for performance-oriented Ford engines and begins opening earlier than the factory thermostat. This allows coolant to flow through the radiator sooner, giving the cooling system additional capacity to manage engine temperatures under demanding conditions.

Effective temperature management becomes particularly important on modified vehicles and during prolonged high-load driving on the race track or spirited mountain-pass driving. The Reische thermostat is therefore an excellent addition to an upgraded cooling system and works particularly well in combination with our Ford Racing M-8501-M52A High-Flow Water Pump.

Proven in numerous Schropp builds

We have been using the Reische 170°F Performance Thermostat in a wide range of Mustang projects for many years. Combined with the Ford Racing M-8501-M52A High-Flow Water Pump, we also use this setup in our own 2003 Mustang track car with a Gen 2 Coyote swap, including race-track use at the Hockenheimring.

We have also installed this combination of performance thermostat and high-flow water pump in numerous customer cars used regularly on the race track as well as in our Schropp SF700 supercharger builds. For us, an effective and properly matched cooling system is an important part of the overall setup whenever an engine is subjected to high and sustained loads.

170°F – a deliberate balance between stock and extreme low-temperature thermostats

The Reische Performance Thermostat begins opening at approximately 170°F / 77°C. Reische deliberately selected this opening temperature to provide a balance between earlier coolant flow under demanding conditions and sensible warm-up and everyday performance.

Unlike very low 160°F thermostats, the objective is not to keep the engine as cold as possible at all times. Instead, the earlier opening point gives the cooling system an earlier opportunity to dissipate heat through the radiator.

Particularly useful for tuned and modified engines

A lower-temperature thermostat does not create additional engine power by itself. It is particularly useful on performance-modified and appropriately calibrated vehicles as well as engines that are regularly subjected to high thermal loads.

Lower and, importantly, more stable coolant temperatures can help reduce thermal stress on the engine and provide more consistent operating conditions during repeated high-load use.

Important information about ECU calibration and temperature monitoring

Installing the Reische 170°F thermostat does not automatically require an ECU tune. Depending on the vehicle, model year and ECU calibration, however, the relevant coolant-temperature monitoring thresholds may need to be checked and, where necessary, adjusted.

The factory diagnostic strategy monitors, among other parameters, whether the engine reaches the expected coolant temperature within a defined period. Because the 170°F thermostat begins opening earlier, some vehicles may operate at coolant temperatures below those expected by the factory diagnostic calibration. In this situation, diagnostic trouble code P0128 – Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature) may be triggered. This is sometimes interpreted as the engine running too cool or the thermostat being stuck open.

For vehicles with a custom ECU calibration, we therefore recommend checking the relevant coolant-temperature thresholds and cooling-fan settings and adjusting them where necessary to suit the 170°F thermostat.

OEM-based design

Reische Performance thermostats use an OEM-based design and OEM components. Particular attention is given to the bypass-valve configuration to ensure that the intended coolant circuit is not compromised by an incorrectly designed low-temperature thermostat.

The 170°F thermostat also provides faster warm-up and better cold-weather behaviour than a 160°F thermostat, making it particularly suitable for performance-oriented street cars that are not used exclusively on the race track.

Product features

• 170°F / approx. 77°C opening temperature
• Earlier coolant flow to the radiator than with the factory thermostat
• Designed for performance-oriented and modified engines
• OEM-based design using OEM components
• Designed to maintain correct coolant bypass operation
• Better warm-up and cold-weather performance than extreme 160°F solutions
• Ideal as part of a properly matched performance cooling system
• Excellent complement to the Ford Racing M-8501-M52A High-Flow Water Pump

Vehicle applications

• Mustang GT 5.0 2011–2026
• Mustang Dark Horse 5.0 2024–2026
• Mustang Mach 1 5.0 2021–2023
• Mustang Bullitt 5.0 2019–2020
• Mustang 3.7 V6 2011–2017
• Shelby GT350 / GT350R 5.2 2015–2020

Not suitable for Mustang 2.3 EcoBoost or Shelby GT500.