Engine Coolant Thermostat Guide for the 2013-2017 Ford Ranger T6
Solving engine temperature problems in your international Ford Ranger.
- Verify you own the international T6 Ranger, as this model was not sold in North America.
- A stuck-open thermostat causing a P0128 code is the most common failure.
- When installing, ensure the new thermostat's jiggle valve is positioned at the top to allow air to escape.
- Given the low part cost and mixed aftermarket reviews, consider using an OEM part to ensure reliability.
A Note for North American Owners
Symptoms of a Failing Thermostat
A thermostat can fail in two ways: stuck open or stuck closed. A stuck-open thermostat is the most common failure for the Ford Ranger.
- Stuck Open: When the thermostat is stuck open, coolant constantly circulates through the radiator. This prevents the engine from reaching its proper operating temperature. You'll notice the temperature gauge stays low, your cabin heater blows lukewarm air, and your fuel economy may decrease. This condition often triggers a Check Engine Light with the code P0128 (Coolant Temperature Below Thermostat Regulating Temperature).
- Stuck Closed: This is a more serious problem. A stuck-closed thermostat traps heat in the engine, preventing coolant from reaching the radiator. This will cause the engine to overheat quickly, potentially leading to major engine damage. If you see the temperature gauge climbing into the red, pull over immediately and shut off the engine.
Choosing the Right Aftermarket Part: OEM vs. Aftermarket
When replacing your thermostat, you have a choice between Original Equipment Manufacturer (OEM) and aftermarket parts. For a critical yet inexpensive part like a thermostat, the decision is worth considering.
Aftermarket brands like Motorad are widely available and affordable. Motorad is a large company that manufactures parts for many brands, including some OEMs. However, owner and mechanic reviews for their direct aftermarket products are mixed. Some users report they work perfectly, while others have experienced premature failures. There is a general belief that OEM-specified parts may have stricter quality control than parts sold under a company's own aftermarket brand name. Given the low part cost, many mechanics and owners prefer to use an OEM thermostat to avoid the risk of having to do the job twice.
Pro Tip: Replace the Gasket
Always install a new gasket or O-ring with your new thermostat, even if the old one looks okay. Most new thermostats come with one. This ensures a proper seal and prevents coolant leaks.
Estimated Costs
| Part Type | Estimated Cost |
|---|---|
| New Aftermarket (Motorad) | $10 - $20 |
| New OEM | $25 - $50 |
| Shop Labor | $100 - $225 |
Frequently Asked Questions
What is the P0128 trouble code?
P0128 is a diagnostic trouble code that means the engine control module (ECM) has detected that the engine is not reaching its required operating temperature within a specific amount of time. The most common cause for this code is a thermostat that is stuck open.
Is an OEM thermostat really better?
For many parts, aftermarket quality is excellent. However, for a thermostat, the cost difference is small compared to the labor involved in replacing it. Many mechanics and experienced owners recommend using an OEM part to ensure reliability and proper temperature regulation, as aftermarket versions can sometimes have slightly different opening temperatures or a higher failure rate.
Can I drive with a bad thermostat?
If it's stuck open (engine running cold), you can drive short distances, but it's not ideal. Your engine will run inefficiently, use more fuel, and produce more emissions. If it's stuck closed (engine overheating), you should not drive the vehicle at all. Overheating can cause severe and expensive engine damage like a warped cylinder head.
What is the 'jiggle valve' and why is it important?
The jiggle valve, or jiggle pin, is a small valve on the flange of the thermostat. Its purpose is to allow trapped air to bleed out of the cooling system. When installing the new thermostat, it is critical to position this valve at the very top (12 o'clock position) to ensure any air in the system can escape to the radiator.
Technical Specifications
The most important specification is the temperature rating (e.g., 195°F / 90°C), which should match the original part for your specific engine (2.2L or 3.2L diesel).
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 Ranger: