A Ford Focus Owner's Guide to the 2013-2018 Engine Coolant Thermostat
Is your Ford Focus engine running too cold or overheating? Your thermostat might be the problem.
- A P0128 check engine light on a 2013-2018 Focus almost always means you need a new thermostat.
- The thermostat is sold as a complete housing assembly; you cannot buy just the valve inside.
- For a daily driver, choose an OEM Motorcraft part or a quality aftermarket brand like Gates; avoid lower-temperature 'racing' thermostats.
- While replacing the thermostat, inspect the coolant reservoir for cracks, as this is another common failure point on these cars.
Is Your Ford Focus Thermostat Failing?
A thermostat failure can happen in two ways: stuck open or stuck closed. Each has its own distinct set of symptoms. Knowing the signs can help you diagnose the problem before it causes more damage.
Symptoms of a Bad Thermostat
- Check Engine Light: This is often the first sign. A code like P0128 means the engine isn't warming up as expected, which usually points to a thermostat that's stuck open.
- Heater Not Working or Blowing Lukewarm Air: If the thermostat is stuck open, the engine never reaches its ideal operating temperature. As a result, there isn't enough heat to warm up the cabin in cold weather.
- Engine Overheating: If the thermostat is stuck closed, it traps coolant in the engine and doesn't allow it to flow to the radiator. This is a serious condition that can cause major engine damage if you continue to drive.
- Low Temperature Gauge Reading: You might notice the temperature needle on your dashboard stays on the 'C' or only moves up slightly, even after driving for a while. This indicates a stuck-open thermostat.
- Coolant Leaks: The plastic thermostat housing on the Focus can become brittle over time and crack, leading to coolant leaks. You might see puddles of orange or yellow fluid under your car.
Known Issue: Engine Block Heater Recall
While not the thermostat itself, there is a major safety recall for many 2013-2018 Ford Focus models equipped with a 2.0L engine and an accessory engine block heater. The heater can crack, leak coolant, and create a fire risk when plugged in. Owners are advised not to use the block heater until it has been replaced by a dealer. You can check if your vehicle is affected on the NHTSA website using your VIN.
Choosing the Right Aftermarket Thermostat
For the 2013-2018 Ford Focus, the thermostat is typically sold as a complete assembly with the housing. When choosing a replacement, you don't have to buy the most expensive part to get good quality.
Brand Quality Tiers
- OEM (Original Equipment Manufacturer): Motorcraft is Ford's own brand. It's the benchmark for fit and quality and a guaranteed safe choice.
- Premium Aftermarket: Brands like Gates are well-respected in the industry for cooling system parts and are considered a reliable alternative to OEM.
- Performance Aftermarket: Mishimoto offers 'racing' thermostats that open at a lower temperature. While this can help highly modified engines run cooler, it is not recommended for a stock daily-driven Focus. It can prevent the engine from reaching its proper operating temperature, hurting fuel economy and potentially triggering a P0128 check engine light.
- Standard Aftermarket: Brands like Calorstat and Facet offer a good balance of quality and price. Calorstat is known to be an OEM supplier for some car manufacturers and is generally considered a solid budget-friendly option.
Pro Tip: Since you'll be draining the coolant for this job, it's a great time to replace it. Ford has updated its recommendation from Motorcraft Orange coolant to Motorcraft Yellow coolant, which is backward-compatible. 🎬 See how to drain, refill, and bleed your coolant system Also, inspect the plastic coolant reservoir, as they are known to crack on these models.
Cost to Replace a Ford Focus Thermostat
The cost can vary based on whether you do it yourself or have a shop perform the work. The part itself is not very expensive, but labor can add up due to the tight access.
| Part or Service | Estimated Cost |
|---|---|
| New Aftermarket Thermostat Assembly | $14 - $92 |
| New OEM (Motorcraft) Thermostat Assembly | $50 - $140 |
| Shop Labor | $220 - $325 |
| Total Professional Replacement | $270 - $465 |
Frequently Asked Questions
Is it hard to replace the thermostat on a 2013-2018 Ford Focus?
It is considered an intermediate-level DIY job. Access is tight, as the thermostat is located under the intake manifold area. The process involves draining coolant, removing some air intake parts, swapping the housing, and then refilling and bleeding the air out of the system. 🎬 Watch this step-by-step thermostat housing replacement walkthrough It typically takes 1.5 to 3 hours.
What is the P0128 code on my Ford Focus?
The P0128 code means "Coolant Temperature Below Thermostat Regulating Temperature." This almost always indicates that your thermostat is stuck in the open position, preventing your engine from warming up properly.
Can I just replace the thermostat and not the whole housing?
No. For this generation of Ford Focus, the thermostat is integrated into the housing and sold as a single assembly. This makes the replacement simpler as you don't have to worry about seating a separate thermostat and gasket correctly.
Should I use an OEM Motorcraft thermostat or is aftermarket okay?
Both are good options. A Motorcraft part guarantees a perfect fit, but a quality aftermarket brand like Gates or Calorstat will also perform reliably and can save you money. Avoid off-brand, no-name parts, as a failed thermostat can lead to serious engine problems.
Helpful Videos
Technical Specifications
OEM Part Numbers: CP9Z-8592-G CM5Z-8575-A FR3Z-8575-A
For most 2013-2018 Ford Focus models (especially the 2.0L engine), the part is an integrated thermostat and housing assembly. The standard opening temperature is around 180°F-195°F (82°C-90°C).
We Have This Part in Stock
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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