Ford Expedition Engine Coolant Thermostat Guide (2016-2022)
Experiencing overheating or strange temperature readings in your Expedition? Your thermostat might be the culprit.
- The original OEM thermostat on 2016-2022 Expeditions is a known failure point for sticking.
- A stuck-open thermostat will trigger a P0128 code, while a stuck-closed one will cause rapid overheating.
- Ford released an updated Motorcraft thermostat (e.g., RT-1252) to fix the sticking issue.
- When replacing, it's best to use the complete thermostat and housing assembly to prevent future leaks.
Is Your Expedition's Thermostat Failing?
A bad thermostat can cause problems that seem complicated but often point back to this simple part. The most common issues are the thermostat getting stuck open or stuck closed. Both situations can cause trouble for your Expedition's 3.5L EcoBoost engine.
Symptoms of a Faulty Thermostat:
- Overheating: If the thermostat sticks closed, it traps coolant in the engine, preventing it from reaching the radiator. This is a serious issue that can lead to major engine damage.
- Engine Running Too Cold: A thermostat stuck open allows coolant to circulate constantly. The engine will take a very long time to warm up, your heater may not blow hot air, and you might see a Check Engine Light with code P0128.
- Temperature Fluctuations: If you see the temperature gauge swinging wildly, especially going up on hills 🎬 Watch: Troubleshooting overheating issues and replacing the thermostat or under acceleration and then dropping, it could be a sign of a sticking thermostat.
- Poor Fuel Economy: An engine that doesn't reach the correct operating temperature is less efficient, leading to worse gas mileage.
A Note on OEM Thermostat Issues
Ford Expedition and F-150 owners from this generation have reported issues with the original factory thermostat sticking. Ford released a redesigned Motorcraft thermostat to address this problem. When replacing your thermostat, it's important to know that even the OEM part had known flaws, making quality aftermarket options a strong consideration.
Choosing the Right Aftermarket Thermostat
For the 2016-2022 Expedition, the thermostat is often sold as an assembly with the housing. When choosing a replacement, you have several options. The brands available in our inventory—Gates, Mishimoto, and Motorad—each have their place in the market.
- Gates: A well-regarded aftermarket brand, Gates is often considered a reliable, OE-quality equivalent. However, in recent years, some Gates thermostats have been manufactured by Motorad and re-boxed, a common practice in the industry.
- Motorad: Motorad is a massive manufacturer that produces thermostats for many brands, including some OEM applications. While some users have had success, others report premature failures, particularly with their "Fail-Safe" models which are designed to lock open upon failure. A standard Motorad thermostat is generally a budget-friendly choice.
- Mishimoto: Often viewed as a performance or premium aftermarket brand, Mishimoto offers thermostats that may feature lower activation temperatures for owners seeking to run their engines slightly cooler, which can be popular in modified or hard-working trucks. Some forum users opt for lower-temperature thermostats to combat overheating concerns.
Pro Tip: Given the known issues with the original Ford thermostat design, opting for the redesigned Motorcraft part (like the RT-1252) 🎬 See this step-by-step guide for replacing the thermostat assembly or a quality aftermarket equivalent from a trusted brand is a smart move. Some owners prefer a slightly cooler 170° or 180° thermostat, but this is often not necessary unless you have specific performance modifications or towing needs.
Cost of Replacing Your Expedition's Thermostat
| Part Type | Average Cost |
|---|---|
| New OEM (Motorcraft) | $20 - $40 |
| New Aftermarket (Gates, Motorad, etc.) | $20.64 - $68.95 |
| Shop Labor | $150 - $250 |
Frequently Asked Questions
Is there a recall for the 2016-2022 Expedition thermostat?
No, there are no specific recalls for the engine coolant thermostat on the 2016-2022 Ford Expedition. However, there is a Technical Service Bulletin (TSB SSM 50835) for some 2021-2022 models that mentions a potential coolant leak at the thermostat housing.
Can I replace the thermostat myself?
Yes, for a DIYer with moderate experience, this is a manageable job. It involves draining some coolant, removing the air intake components to get access, unbolting the housing, and swapping the part. The key is ensuring the system is properly bled of air afterward to prevent overheating. Estimated time is 1-2 hours.
🎬 Watch this DIY walkthrough for a smooth thermostat replacementShould I replace just the thermostat or the whole housing assembly?
For this generation of Expedition, the thermostat and housing are often sold as a single assembly. It is highly recommended to replace the entire unit. This ensures you have a new gasket and eliminates the risk of the old plastic housing being brittle or cracked, which can cause leaks.
What is the P0128 code?
P0128 means "Coolant Temperature Below Thermostat Regulating Temperature." This code is triggered when your engine's computer detects that the engine isn't warming up as quickly as it should. The most common cause by far is a thermostat that is stuck open.
Helpful Videos
Technical Specifications
OEM Part Numbers: HL3Z-8575-B HL3Z-8575-A BL3Z-8575-A RT-1238 RT-1252
The OEM thermostat is typically a 190°F or 195°F design. The part is most commonly sold as a complete assembly including the plastic housing and integrated gasket. The 3.5L EcoBoost engine requires precise temperature control.
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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