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How to Install: Mishimoto Racing Thermostat

Delete / Lock. How to Install: Mishimoto Racing Thermostat

Here is quick / rough guide on how to install the Mishimoto Racing Thermostat without having to remove the front half of the car. Please read prior to attempting to install. Hope this helps.

Mishimoto Thermostat: https://www.mishimoto.com/ford-fiesta-st-2014-thermostat.html

Before doing please do the following:

-Disconnect battery
-Invest in a External torx socket set. (https://www.amazon.com/GearWrench-8...pID=31XTCfBxRCL&preST=_SX300_QL70_&dpSrc=srch )
-Invest in hose pinch pliers ( https://www.amazon.com/Motivx-Tools...pID=41Z5Cf5YSsL&preST=_SY300_QL70_&dpSrc=srch )
-Purchase a gallon of coolant 50/50 or concentrate + distilled water.

1)… Remove the following: Passenger side headlight, Disconnect coolant hoses from reservoir tank and remove coolant reservoir, Below the car there is a plastic cover that is covering the pulleys ( 2x T30 screws)

2)…Next get a 17mm spanner move the tensioner then remove the accessory belt. You just simply slip the belt from the alternator side and the idle pulley right below the alternator.

3)…Now to remove the alternator and the Idle pulley. There are three fasteners total attaching the alternator. Two on top and one towards the bottom. All are 15mm, Idle pulley bolt is 10mm. You would also need to use an External Torx socket to remove the stud on the top alternator bolt. REINSTALL: Torque the alternator stud to 7 ftlbs. The fasteners to 35 Ftlbs. Idle pulley to 18 Ftlbs. When reinstalling i'd recommend putting the bottom alternator bolt on first then the top two.

4)… Disconnect Alternator (13mm bolt), and electrical connector.

5)… Now you have access to the Thermostat housing. Before continuing you would have to back out the A/C compressor a little. If this isn’t done the lower portion of the thermostat housing will get snagged by a small portion of the A/C compressor. There are 3 fasteners total, 1 on top, 2 below. I would suggest completely loosening one at a time and screwing it back in so the compressor is still attached by a few threads. REINSTALL: Torque the 3 bolts at 17ftlbs.

6)… Disconnect electrical connector and plastic fastener that hold the alternator power wire, as well as hose clamp. There is also a retainer clip holding a coolant hose to the component on the thermostat housing shown in green in step 7, remove the clip and slide off the hose. There are 4 screws that hold the thermos stat housing. Two on top two right below the housing. They are all 8mm screws. REINSTALL: torque them down to 7 ftlbs.

7)… Before removing the 4 screws that hold the thermostat housing first disconnect the component shown in green. There are two 8mm bolts holding it down. REINSTALL: torque these would be 7ft lbs as well.

8)… Lastly remove the 4 bolts and holding the thermostat housing and then remove the hose clamp.

9) Now you just got remove the hold thermostat by pushing down and twisting the retainer. Then install the mishimoto thermostat the same way / position the old one is. Don’t forget to replace the gasket and make note of the position of the bubbler hole.


Last edited:


5000 Post Club
Staff Member
Premium Account
Great write-up and thank you!

San Diego, CA, USA
Well I installed the thermostat using the instructions and the job took me about 2hours. I have a oil cooler installed too and the cars coolant is staying under 200 degrees now with city driving multiple people in the car a/c blasting and 90 degree weather. I think the combo of the oil cooler and 160 degree thermostat has solved my over heating problems for now. I'll let you guys know what happens next time I do some hard mountain driving. But I'm thinking it will be fine. Thanks for the write up! I couldn't have done it with out it! Oh and I was quoted 350$ for the install so I saved some money!

Metro Detroit
I can remember when changing, or removing, the alternator took just 5 minutes. BTW there was a time when if you got a stuck thermostat you simply removed it and got back on the road. I can also remember when all you needed to do to fill the radiator was to remove the cap and pour in some anti freeze mix, no need for vacuum filling at all. To say that I am NOT impressed with some aspects of our engine design would be an under statement.

On the plus side this write up is most Excellent.