Ford Bronco Engine Coolant Thermostat Guide (1978-1997)
Keep your Bronco's engine from overheating by understanding, choosing, and replacing your thermostat.
- A failing thermostat can cause your Bronco to overheat (stuck closed) or run too cold (stuck open).
- For stock Broncos, an OEM-spec Motorcraft or quality aftermarket brand like Gates is a reliable choice.
- Always replace the thermostat gasket to prevent coolant leaks.
- Thermostat replacement is a manageable DIY job for most owners of this generation of Bronco.
Is Your Bronco's Thermostat Failing?
A bad thermostat can cause serious engine problems. The most common issue is getting stuck closed, which leads to rapid overheating and can cause severe engine damage. Conversely, if it sticks open, your engine will take a very long time to warm up, especially in colder weather. This can lead to poor fuel economy, increased engine wear, and a heater that doesn't blow hot air. Pay attention to your temperature gauge; if it's suddenly reading much higher or lower than normal, or fluctuating wildly, the thermostat is a likely culprit.
🎬 Learn more about the common symptoms of a failing thermostat.Choosing the Right Aftermarket Thermostat
For the 1978-1997 Bronco, you have several reliable aftermarket thermostat options. The choice often comes down to brand reputation and specific needs, like a lower temperature rating for modified engines.
- OEM/Standard Replacement (Motorcraft, Gates, Calorstat, Motorad): Motorcraft is Ford's original equipment brand and serves as the benchmark for quality and fit. Brands like Gates, Calorstat, and Motorad are well-known aftermarket manufacturers that produce thermostats meeting OEM specifications. While generally reliable for daily drivers, some online forum users have reported mixed experiences with Motorad's longevity, though others have had no issues. These are affordable and widely available options suitable for most stock Broncos.
- Performance (Edelbrock, Mishimoto, Mr. Gasket): If your Bronco is modified for higher performance or used for heavy towing, a performance thermostat might be a good upgrade. Brands like Edelbrock and Mishimoto offer high-flow designs and lower opening temperatures (e.g., 180°F instead of the stock 195°F). A lower temperature thermostat can help the engine run slightly cooler under load. Mr. Gasket also offers performance-oriented options.
Typical Costs for a New Thermostat
| Part Type | Typical Price Range |
|---|---|
| New Aftermarket Thermostat | $7.33 - $68.95 |
| New OEM (Motorcraft) Thermostat | $10 - $30 |
| Shop Labor for Installation | $75 - $150 |
Frequently Asked Questions
What temperature thermostat should I use for my Bronco?
For a stock engine, using the OEM-specified temperature (usually 192°F or 195°F) is recommended for best performance and efficiency. Some owners of modified or hard-working Broncos opt for a 180°F thermostat to aid in cooling. Using a thermostat that is too cool can negatively affect fuel economy and engine performance.
Is replacing a thermostat a good DIY job?
Yes, for most 1978-1997 Broncos, this is a relatively simple DIY task. It's located at the front of the engine where the upper radiator hose connects to the engine block. The job requires basic hand tools, draining some coolant 🎬 Watch this guide on how to test and replace your thermostat., and cleaning the gasket surfaces. However, bolts on the thermostat housing can sometimes be corroded and difficult to remove, so be prepared with penetrating oil.
🎬 See how to remove a frozen or stuck thermostat housing.What are the signs of a coolant leak from the thermostat housing?
You may notice coolant dripping from the area where the upper radiator hose meets the engine. You might also see crusty, colored residue (usually green or orange) around the thermostat housing. A leaking housing can lead to low coolant levels and overheating.
Are there any recalls for the 1978-1997 Ford Bronco thermostat?
No, searches of the National Highway Traffic Safety Administration (NHTSA) database and other sources did not find any recalls or common Technical Service Bulletins (TSBs) related to the engine coolant thermostat for the 1978-1997 Ford Bronco models.
Helpful Videos
Technical Specifications
OEM Part Numbers: F5TZ8592CA RG605
Common temperature ratings are 180°F, 192°F, and 195°F. The thermostat is typically located inside a housing where the upper radiator hose connects to the engine intake manifold. A paper or composite gasket is required for sealing.
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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.