A Guide to the Engine Coolant Thermostat for the 1982-1993 Dodge D150
Keep your classic Dodge D150's engine running at the perfect temperature with the right thermostat.
- A stuck-closed thermostat will cause critical overheating; a stuck-open one will prevent the engine from warming up properly.
- For stock trucks, use a quality 195°F thermostat from a brand like Gates.
- Be cautious with budget brands like Motorad, as they have a reputation for premature failure.
- If you have an aftermarket intake manifold, verify the required thermostat diameter before purchasing a replacement.
Is Your D150's Thermostat Failing?
A thermostat is a common wear item. When it fails, it usually gets stuck in one of two positions: open or closed. Both can cause problems for your truck.
Stuck Closed: A Critical Failure
This is the most dangerous type of failure. A stuck-closed thermostat prevents coolant from reaching the radiator, causing the engine to overheat very quickly. If you see your temperature gauge climbing into the red, pull over and shut off the engine immediately to prevent serious damage like a blown head gasket.
Stuck Open: A Less Obvious Problem
If the thermostat is stuck open, coolant constantly flows to the radiator. This makes it difficult for your engine to reach its proper operating temperature. Symptoms include the temperature gauge staying low, poor heater performance in the winter, and potentially worse fuel mileage.
🎬 Watch: How to test for symptoms of a bad thermostatChoosing the Right Aftermarket Thermostat
For a vehicle like the 1982-1993 D150, original Mopar parts can be hard to find. The aftermarket offers a wide selection, but quality varies. Here’s how the available brands stack up based on owner experiences and reputation.
Tier 1: Performance & Heavy-Duty
These brands are for owners who want different temperature options for performance use or heavy towing. They generally have a good reputation for quality.
- Mishimoto: Known for high-quality cooling components, Mishimoto offers thermostats that are well-regarded but come at a higher price. They offer options that open at different temperatures, which can be useful for specific applications.
- Edelbrock & Mr. Gasket: These are trusted names in the performance world. They often provide lower-temperature thermostats (160°F or 180°F) for modified engines.
A Note on Aftermarket Intakes
If your D150 has an aftermarket intake manifold, like an Edelbrock Performer, be aware that it may require a larger diameter thermostat than the stock manifold. Some owners have found a standard replacement thermostat is too small and can fall into the intake. Measure your old part or check the intake manufacturer's specifications before buying.
Tier 2: Reliable OEM-Style Replacement
For a daily driver or stock truck, a standard replacement that matches the factory 195°F temperature is the best choice.
- Gates: Gates is a widely respected aftermarket brand for cooling system parts, including thermostats. They are often recommended on forums as a reliable, no-frills option that works as expected.
Tier 3: Budget Options (Use with Caution)
While the low price is tempting, some brands have a mixed reputation for quality and reliability.
- Motorad: This brand has a controversial reputation. Many mechanics and DIYers on forums report a high rate of failure right out of the box or shortly after installation. While some have no issues, the number of negative reports suggests caution. Their "fail-safe" thermostats, designed to lock open upon failure, are also frequently criticized.
Aftermarket Thermostat Cost for 1982-1993 Dodge D150
| Item | Estimated Cost |
|---|---|
| Aftermarket Thermostat Part | $8.47 - $56.13 |
| Thermostat Gasket | $1 - $5 (Often included with thermostat) |
| Shop Labor | $75 - $150 |
| Total Estimated Cost (DIY) | $9 - $61 |
| Total Estimated Cost (Installed) | $84 - $211 |
Frequently Asked Questions
What temperature thermostat should I use?
For a stock D150, a 195°F thermostat is the factory specification and the best choice for overall performance and efficiency. Using a lower temperature thermostat (e.g., 180°F) on a stock engine can lead to reduced fuel economy and may affect emissions. Performance-modified engines may benefit from a lower temperature thermostat as specified by the engine builder.
Do I need to replace the gasket?
Yes, always use a new gasket when replacing the thermostat. It's a cheap part that ensures a leak-free seal. Many thermostats come with a new gasket. For older trucks with pitted mating surfaces, applying a thin layer of RTV silicone gasket maker can help ensure a good seal.
My truck still overheats after replacing the thermostat. What's wrong?
If you're still overheating with a new thermostat, there could be several causes. First, you could have a defective new part, which is common with budget brands. Second, the thermostat may have been installed backwards. Third, and most common, is trapped air in the cooling system, which needs to be properly "burped" out. 🎬 See how to diagnose and fix persistent overheating issues Other potential issues include a clogged radiator, a failing water pump, or a bad fan clutch.
🎬 Watch this guide on troubleshooting Dodge Ram overheating problemsWhat is a "fail-safe" thermostat?
A "fail-safe" thermostat is designed to lock in the open position if the engine overheats once. While this prevents a catastrophic stuck-closed failure, it means you have to replace the thermostat again to get your engine and heater to work properly. Many mechanics find them to be more trouble than they're worth.
Helpful Videos
Technical Specifications
Standard Temperature: 195°F (89°C). Performance Temperatures: 160°F, 180°F. Gasket Type: Paper or rubber. Housing Bolts: 2.
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.
- Dodge D150:
- 🎬 Helpful Videos
- 🛍️ Shop This Part
- Is Your D150's Thermostat Failing?
- Stuck Closed: A Critical Failure
- Stuck Open: A Less Obvious Problem
- Choosing the Right Aftermarket Thermostat
- Tier 1: Performance & Heavy-Duty
- A Note on Aftermarket Intakes
- Tier 2: Reliable OEM-Style Replacement
- Tier 3: Budget Options (Use with Caution)
- Aftermarket Thermostat Cost for 1982-1993 Dodge D150
- Frequently Asked Questions
- 🎟️ Get 5% Off