A Guide to the Engine Coolant Thermostat for the 2011-2019 Ford Fiesta
Understand the signs of a failing thermostat in your Fiesta and how to choose the right replacement part.
- A thermostat stuck closed will cause rapid overheating and can destroy your engine; pull over immediately.
- A thermostat stuck open is less urgent but will cause poor fuel economy, no heat, and a P0128 check engine light code.
- For most Fiesta owners, a Motorcraft (OEM) or high-quality aftermarket brand like Gates is the best choice.
- Consider replacing the entire thermostat and housing assembly, as the plastic housing is a common point of failure.
Is Your Ford Fiesta Thermostat Failing?
A bad thermostat can cause serious problems for your 2011-2019 Ford Fiesta. It most often fails by either sticking open or sticking closed. Both situations can cause trouble, but a stuck-closed thermostat is an emergency.
Symptoms of a Bad Thermostat
- Engine Overheating: If the thermostat sticks closed, it traps coolant in the engine, preventing it from reaching the radiator. Your temperature gauge will quickly climb into the red, and you may see a warning light. This is the most serious symptom and can lead to severe engine damage if you continue to drive.
- Engine Slow to Warm Up: If the thermostat sticks open, coolant will flow to the radiator all the time. This makes it take much longer for your engine to reach its normal operating temperature.
- Check Engine Light: A thermostat that is stuck open will often trigger the check engine light with a P0128 code. This code means the engine's coolant temperature is below what it should be.
- Poor Heater Performance: Your car's heater uses hot coolant to warm the cabin. If the engine isn't getting hot enough because the thermostat is stuck open, you may notice the heater blows lukewarm or cold air.
- Temperature Gauge Fluctuates: A faulty thermostat can cause the temperature gauge on your dashboard to move erratically, swinging from cool to hot.
- Coolant Leaks: The thermostat is often located in a plastic or aluminum housing. These housings can crack over time, leading to coolant leaks. You might notice puddles of orange or yellow coolant under your car.
Choosing a Replacement Thermostat
When shopping for a new thermostat for your Fiesta, you have several options. Not all aftermarket parts are created equal. Here’s a breakdown of the brands available.
| Brand Tier | Brands | General Quality & Notes |
|---|---|---|
| OEM | Motorcraft | Motorcraft is Ford's official parts brand. Choosing an OEM thermostat guarantees the correct fit and temperature rating for your Fiesta. It is the safest and most reliable option. |
| Quality Aftermarket | Gates, Calorstat, Facet | Gates is a well-respected aftermarket brand known for quality cooling system components. Calorstat and Facet are also considered reliable aftermarket choices, often viewed as a step above budget brands. |
| Performance (Fiesta ST) | Mishimoto | Mishimoto offers a lower-temperature racing thermostat for the Fiesta ST model. It opens earlier (at 160°F) to keep the engine cooler during high-performance driving. This is not recommended for standard daily driving, especially in colder climates, as the engine may not reach its ideal operating temperature. |
| Budget Aftermarket | Motorad | Motorad is a budget-friendly option, but owner reviews are very mixed. Some have experienced premature failures, while others have had no issues. Given the critical role of the thermostat, it may be worth spending a little more for a more trusted brand. |
Frequently Asked Questions
What is a P0128 code?
The P0128 code means "Coolant Temperature Below Thermostat Regulating Temperature." Your car's computer has detected that the engine is not warming up as quickly as it should. The most common cause for this code is a thermostat that is stuck in the open position.
Are there any recalls on the Ford Fiesta thermostat?
There are no specific recalls for the thermostat on the 2011-2019 Ford Fiesta. However, a related recall (17S09) was issued for some models due to potential cylinder head cracking from overheating, which highlights how important a working cooling system is for this car.
Can I replace the Fiesta thermostat myself?
Yes, this is a DIY-feasible job for someone with moderate mechanical skill. Access is tight on the 1.6L engine, and the job often requires removing the alternator to reach the thermostat housing. You will also need to drain, refill, and bleed the cooling system. If you are not comfortable with this, a professional mechanic can do the job in 1.5-2.5 hours.
Should I get a lower temperature thermostat for my Fiesta?
For a standard, non-turbo Fiesta, you should use a thermostat with the factory temperature rating. For the high-performance Fiesta ST, a lower temperature thermostat from a brand like Mishimoto is an option for track use or aggressive driving. However, for a daily-driven ST, it can prevent the engine from reaching its most efficient operating temperature, especially in winter.
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Technical Specifications
OEM Part Numbers: BE8Z-8575-Z RT-1211
Fits 2011-2019 Ford Fiesta with 1.6L engine. Temperature ratings vary by model year and engine type, with stock thermostats typically opening between 180°F and 207°F. Always verify the correct part for your specific vehicle.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
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