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Reische Performance

Reische Performance FORD-4D GEN-3 170° Performance Thermostat


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Mustang performance parts, performance and tuning
Customer Reviews


Reische's latest 3rd generation Ford-4D thermostat has been upgraded with modern features like a rubberized diaphragm and a larger heat motor. It's a direct-fit unit with proper bypass control so you're guaranteed maximum efficiency from your cooling system. All components are mfg by your OEM supplier making this the very best available for your application.

Whether you are using an aftermarket radiator or not, this thermostat will provide the best possible heat dissipation from your setup and even deliver better overall performance than our competitor's 160° thermostats. Reische believes the 170° opening temp is the ideal balance for high performance engines, providing high flow to your radiator by mid-180 temps along with good all season performance. With proper fan settings your coolant temps in cool weather will be in the 170s and in hot weather the 180s, giving those running high levels of timing and/or boost added protection against engine-damaging detonation as well as maximum hp.

All Reische Performance thermostats are backed by a 5 YEAR WARRANTY.

2011-2019 Explorer 3.5L
2010-2019 Flex 3.5L
2010-2019 Taurus 3.5L
2005-2006 Mustang 4.6L
2003-2004 Mercury Marauder 4.6L
1996-2004 Cobra & Mach 1 4.6L


Fan ECT1 High On: 190°
Fan ECT2 High On: 190°
Fan High Off: 186°
Fan Low Off: 182° (shuts off @180°)
Fan Low On: 184°

Low Fan Speed: 186° (shuts off @178°)
High Fan Speed: 190°

Ideally the fan settings in your tune should be lowered to see the best possible heat dissipation from your cooling system. Otherwise a low temp thermostat will only be effective when the vehicle is moving because heat cannot be removed unless there is air passing through the radiator. However, there is not a handheld programmer available at this time capable of modifying fan settings in most of the new Ford engine management systems. The fan speed tables will need to be adjusted through a custom tune (available through Lethal Performance) or via tuning software. These new systems estimate coolant temps based on readings from a dry head temp sensor. However these ‘inferred’ ECT values can be more volatile and may read as much as 8-10° hotter than actual coolant temps. This means that a vehicle using our 170° thermostat could see ECT anywhere between 165-205°, depending upon conditions and fan settings. We rely on your feedback, so please let us know if you become aware of any new developments in managing the fan settings for these applications.

Vehicle Application(s)

This product fits the following models and years

SVT Cobra1996 1997 1998 1999 2000 2001 2003 2004
Mustang GT2005 2006
Mach-12003 2004
EXPLORER 3.5L2011 2012 2013 2014 2015 2016 2017 2018 2019
FLEX ECOBOOST2010 2011 2012 2013 2014 2015 2016 2017 2018 2019
TAURUS SHO2010 2011 2012 2013 2014 2015 2016 2017 2018 2019

Customer Reviews 1 item(s)

Exactly what my turbo car needed!
Great product with a great reputation, works exactly as described and this combined with some additive brought my temps down in my turbo Mach 1 almost 15° at idle! Review by Resurrection Motorsports / (Posted on 8/4/2022)

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