Ford Explorer Engine Coolant Thermostat: A Guide for 2018-2024 Models
Understanding thermostat failure in your Explorer and how to choose the right replacement part.
- Thermostat failure can cause either overheating (stuck closed) or a slow warm-up with no heat (stuck open).
- Replacement is expensive due to high labor costs; the part is often in a very difficult-to-access location.
- For this part, using the OEM Motorcraft brand is strongly recommended to ensure reliability and avoid repeat repairs.
- Owners of 2020 3.0L models should be aware that a false overheating signal could be a sensor issue (SSM 49004), not a bad thermostat.
Is Your Explorer's Thermostat Failing?
A bad thermostat can cause serious engine problems. It typically fails in one of two ways: stuck open or stuck closed. Both situations can cause noticeable issues with your vehicle.
Symptoms of a Failing Thermostat
- Engine Overheating: If the thermostat is stuck closed, coolant can't get to the radiator to be cooled. This is the most common and dangerous symptom, causing the engine temperature gauge to spike and potentially leading to severe engine damage.
- Engine Slow to Warm Up: If the thermostat is stuck open, coolant flows to the radiator constantly. This makes it take a very long time for your engine to reach its normal operating temperature, especially in cold weather.
- Poor Heater Performance: A stuck-open thermostat means the coolant may never get hot enough to provide warm air to the cabin. If your heater is blowing cool air, the thermostat could be the reason.
- Check Engine Light: A thermostat that is stuck open or not performing correctly can trigger a Check Engine Light, often with the code P0128 🎬 Watch: How to identify symptoms and test for code P0128 (Coolant Temperature Below Thermostat Regulating Temperature).
- Fluctuating Temperature Gauge: The temperature needle may swing from cool to hot erratically, indicating the thermostat is not regulating temperature correctly.
Known Issue for 2020 3.0L EcoBoost Models
Some 2020 Ford Explorers with the 3.0L EcoBoost engine may experience a false "Engine Coolant Over Temperature" warning. According to Ford's Special Service Message (SSM 49004), this can be caused by a faulty Engine Coolant Temperature (ECT) sensor or its wiring, not the thermostat itself. The symptoms are identical to a stuck-closed thermostat, so proper diagnosis is critical to avoid replacing the wrong part.
🎬 See how to fix the 3.0L Engine Coolant Over Temp warningChoosing the Right Aftermarket Thermostat
When replacing the thermostat on your 2018-2024 Explorer, you have several brand choices. Given the high labor cost for this repair, choosing a quality part is essential to avoid doing the job twice.
Brand Quality Tiers
- OEM (Motorcraft): For a critical part like the thermostat, the original Motorcraft part is widely considered the most reliable option. It is designed specifically for your vehicle's cooling system and is the safest choice to ensure proper performance and longevity. Many professional mechanics and forum users strongly recommend sticking with the OEM part.
- Standard Aftermarket (Gates): Gates is a well-known aftermarket manufacturer. While their parts are generally considered acceptable, some users report that they may not have the same robust construction as OEM thermostats. Given the difficulty of this repair, the small cost savings may not be worth the risk compared to Motorcraft.
- Performance (Mishimoto): Mishimoto specializes in low-temperature "racing" thermostats that open earlier than stock units (e.g., 160°F vs. a stock 190°F). These are intended for highly modified and tuned engines and are not recommended for a stock daily-driven Explorer. Using one can prevent your engine from reaching its optimal operating temperature, which can hurt fuel economy and trigger a Check Engine Light.
- Budget (Motorad): Motorad thermostats have received mixed to negative reviews, with some users reporting premature failures. While their "Fail-Safe" feature is designed to lock the thermostat in the open position upon failure, the overall reliability is a concern for many. It is generally recommended to avoid this brand for such a critical and labor-intensive repair.
A Note on Thermostat Housings
For many 2018-2024 Explorer engines, especially on 2020 and newer models, the thermostat is sold as an integrated assembly with the housing. This is one reason for the high part cost. It is often not possible or recommended to replace only the thermostat valve itself.
How Much Does Thermostat Replacement Cost?
Replacing the thermostat on a 2018-2024 Explorer is more expensive than on many other vehicles due to its location, which often requires significant labor to access. Costs vary by model year, with the newer 2020-2024 generation being significantly more expensive.
| Item | Estimated Cost |
|---|---|
| New OEM (Motorcraft) Part | $60 - $340+ |
| New Aftermarket Part | $18 - $310 |
| Shop Labor | $170 - $860+ |
| Total Professional Replacement (2018-2019) | $780 - $895 |
| Total Professional Replacement (2020-2024) | $920 - $1,200+ |
Cost estimates are based on national averages and may vary by location and specific engine type.
Frequently Asked Questions
Can I replace just the thermostat or do I need the whole housing?
For most 2018-2024 Explorers, especially the 2020+ generation, the thermostat is an integral part of the housing and is replaced as a single assembly. On some older 3.5L V6 engines, it may be possible to replace just the thermostat insert, but it is often recommended to replace the complete housing to prevent leaks.
🎬 Watch this step-by-step guide to replacing the thermostat and housingIs it safe to drive with a bad thermostat?
If your thermostat is stuck closed and the engine is overheating, you should stop driving immediately to prevent catastrophic engine damage. If it's stuck open, you can drive the vehicle, but you should get it repaired soon to avoid poor fuel economy, poor heater performance, and potential long-term wear.
Why is the replacement so expensive?
The high cost is primarily due to labor. On many Explorer engines, the thermostat housing is located in a difficult-to-reach area, sometimes requiring the removal of the intake manifold or other major components to access it.
Should I use a low-temperature 'performance' thermostat?
No, not unless your Explorer is heavily modified and has a custom engine tune that requires it. A low-temp thermostat will cause a stock engine to run too cool, which can reduce efficiency, increase emissions, and may cause a persistent Check Engine Light.
Helpful Videos
Technical Specifications
OEM Part Numbers: FR3Z-8575-A LB5Z-8575-C RT-1233 RT-1262
Thermostats for the 2018-2024 Ford Explorer are typically sold as a complete housing assembly, often with an integrated electronic sensor. Standard opening temperatures are around 190°F (88°C). Performance versions may open at 160°F or 170°F but are not recommended for stock vehicles.
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.
- Ford Explorer:
- 🎬 Helpful Videos
- 🛍️ Shop This Part
- Is Your Explorer's Thermostat Failing?
- Symptoms of a Failing Thermostat
- Known Issue for 2020 3.0L EcoBoost Models
- Choosing the Right Aftermarket Thermostat
- Brand Quality Tiers
- A Note on Thermostat Housings
- How Much Does Thermostat Replacement Cost?
- Frequently Asked Questions
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