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Reische Performance Thermostat - 170 Degree (96-04 Cobra, Mach 1; 05-06 GT)

Market Price $75.99 You Save 17% ($12.99)
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  • Item 397317
  • MPN# Ford-4D

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Ship to: Ashburn - 20149
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    Features & Details

    • Built by Hand from OEM Thermostats
    • Includes OEM diaphragm and Bypass Control
    • Ensures Maximum Cooling Efficiency
    • Direct Replacement Installation
    • Recommended for Tuned Motors, but Tuning Not Required
    • Protects Motor from Damaging Heat
    • Cooler Temps for More Timing Advancement
    • Fits 1996-2004 Cobra, Mach 1, 2005-2006 GT Mustangs
    More Power? Run Cooler. If you're installing a tune on your motor – or generally adding some performance parts to your Pony – its recommended to run a lower temperature thermostat. The Reische Performance Thermostat operates at 170 degrees compared to the 180 to 195 degrees of your OEM unit. This lower temperature threshold ensures your motor runs cooler under more power loads.

    Tune it? Cool it. If you're advancing timing on your motor or operating a custom tune, a lower temperature thermostat is a critical investment in engine life. Lower temperatures allow for safer timing advancement and tuning without causing engine wear or detonation, which can ruin your motor.

    Made to Fit Mustangs. Unlike cheaper, generic units that are "universal", each Reische Performance Thermostat is made using the same diaphragm and bypass control as OEM thermostats. Each unit is modified by hand with U.S made parts to ensure they run at the right temperature for your Mustang.

    All-Weather Capable. Running a lower temperature thermostat has been said to reduce performance – but with the Reische's consistent operation and 170-degree "sweet spot", no drivers have reported any loss of power or MPGs in colder weather.

    Application. The 170-Degree Reische Performance Thermostat is specifically designed as a direct replacement-upgrade for all 96-04 Cobras and Mach 1s, and 2005-2006 GT Mustangs.

    Tuning Note. While no tuning is required for installation, we do highly recommend lowering your fan settings for more consistent coolant temperatures.

    Fitment: 1996 1997 1998 1999 2001 2003 2004 2005 2006 Details

    CA Residents: Warning: California's Proposition 65

    What's in the Box
    • (1) Thermostat
    • (1) Gasket
    • Coolant Ratio/Additive Recommendations
    Installation Info
    Will it fit my Mustang?

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    Customer Reviews (10) Write a Review

    Overall Rating 4.9

    out of 5 stars

    Installation Time:Less than 1 Hour

    • Performance Gain 4 4
    • Fit 5 5

    • 5/5

      Installation Time: Less than 1 Hour

      November 09, 2018


      High quality part. Fit perfect. Very pleased with this purchase.


      Year: 1997 Submodel: Cobra

      Helpful (2)

    • 5/5

      Installation Time: Less than 1 Hour

      October 10, 2018


      Car runs much cooler since installed. Need help since turbo pipe make under hood temperature high.


      Year: 2005 Submodel: GT

      Helpful (3)

    • 4/5

      Installation Time: Afternoon

      July 12, 2018

      Reische Thermostat

      Recently installed this thermostat, i have definitely noticed that my car takes longer to warm up even in 90 deg temps. The stock gauge actually reads lower but eventually after about 15 minutes of driving it will reach its normal halfway position, although actual coolant temps are hovering around 185-190 deg. Ensure to set your high and low fans with your hand held tuner if you have the capabilities.


      Year: 2004 Submodel: Cobra

      Helpful (3)

    • 5/5

      Installation Time: Less than 1 Hour

      June 07, 2018

      Awesome for hot climates

      Living in a humid climate does not help these cars out. Since winter I have seen the temp go up and up, so I tried a lower stat with a Mishi rad. Have not gotten above 190 degrees even in 100 degree weather.


      Year: 1997 Submodel: Cobra

      Helpful (5)

    • 5/5

      March 18, 2018

      Really fast and good product

      Works great ,it helps alot wen is really hot i do recommend it


      Year: 2005 Submodel: GT

      Helpful (6)

    • 5/5

      Installation Time: Less than 1 Hour

      January 20, 2018

      Reische Performance Thermostat, 2004 Cobra

      Fast delivery, easily installed, good temperature control


      Year: 2003 Submodel: Cobra

      Helpful (4)

    • 5/5

      Installation Time: Afternoon

      June 21, 2017

      170° Thermostat

      This is a great replacement for the stock thermostat.


      Year: 2006 Submodel: GT

      Helpful (5)

    • 5/5

      Installation Time: Less than 1 Hour

      June 10, 2017

      Work perfect

      This thermostat work perfect with bama tune excellent combo thanks


      Year: 1997 Submodel: Cobra

      Helpful (4)

    • 5/5

      Installation Time: Less than 1 Hour

      January 12, 2017

      Perfect fit for EcoBoost

      I installed this in my 2014 Taurus SHO. I know this thermostat is mainly for the 4.6L DOHC and 05-06 Mustang GT, but the Reische 4D is also recommended for the transverse 3.5L EcoBoost V6 (SHO, MKS, MKT, Explorer, Flex) engines replacing the stock factory 180F unit. The Reische is different from the Evenflo sold by Livernois (aside from being 170F versus 160F) because it is a modified cold-side thermostat (same as the factory EcoBoost thermostat) and has that unique bypass unit on the bottom. The Evenflo is a modified hot-side thermostat that works in the Mustangs, but you don't want to use that for the EcoBoost motor as it is designed for a cold-side thermostat. I noticed an immediate difference in cooling even without tuning the fan turn on point. While cruising off throttle, the ECT will drop quite a bit (into the 170s). While on throttle in cruising conditions, the ECT will try to stay around the 180s. Cold starts and warmups are not affected, nor is my heater output in single digit winters affected. I currently have my fan turning on at the stock setting, but will adjust it once I get more datalogging done. I will most likely just set it to turn on around 190F to prevent the fan from running all the time even in the winter but as far as I can tell, a tune isn't required as there's nothing that important to tune for the thermostat other than fan turn on points and when to switch base fuel tables - which will work fine as-is. I extracted about a gallon of coolant from the degas bottle before removing the housing to swap thermostats. The gasket is included with the Reische and it is just a standard Motorcraft RG-571 from the looks of it.


      Year: 2007 Submodel: GT

      Helpful (5)

    • 5/5

      Installation Time: Less than 1 Hour

      January 11, 2017

      Great replacement

      The stock thermostat i had before broke so I was looking for a cheap replacement. I found this one and it is so much better


      Year: 2016 Submodel: GT

      Helpful (7)

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