Dodge Dart Engine Coolant Thermostat Guide (1960-1978)
Choosing the right thermostat is key to keeping your classic Dart's engine happy, whether it's a Slant Six or a V8.
- Aftermarket thermostats are the only practical option; OEM parts are not readily available.
- Choosing the correct temperature (180°F vs. 195°F) is more important than the brand.
- Stick with reputable standard replacement brands like Stant or Gates for reliability.
- Always test a new thermostat in a pot of hot water before installation to ensure it works.
Is Your Dart's Thermostat Failing?
A thermostat is a simple mechanical part that wears out over time. It can fail in two ways: stuck open or stuck closed. Both can cause problems for your Dart's Slant Six or V8 engine.
| Symptom | If Stuck Open | If Stuck Closed |
|---|---|---|
| Engine Temperature | Takes a very long time to warm up, or temperature gauge stays on 'C'. | Engine overheats quickly. Temperature gauge shoots to 'H'. This is critical. |
| Heater Performance | Little to no heat from the cabin heater, even after driving for a while. | Heater performance is not the primary symptom; overheating is the main concern. |
| Engine Performance | Poor fuel economy and sluggish performance as the engine never reaches its ideal operating temperature. | Severe engine damage, including warped cylinder heads and blown head gaskets, can occur if the engine is not shut off immediately. |
Choosing the Right Aftermarket Thermostat
For a vehicle from the 1960-1978 era, new original equipment (OEM) parts are generally not available. The market consists of new aftermarket parts, which are the standard for repairs on these classic cars. The most important choice you'll make is the temperature rating.
Temperature Rating: 180°F vs. 195°F
Your Dart was originally equipped with either a 180°F or 195°F thermostat, depending on the year and emissions equipment.
- 180°F: Generally used on earlier models (pre-1970) and is often preferred by owners today for slightly cooler running, especially in warmer climates or with performance-modified engines.
- 195°F: Became standard in the early 1970s to improve emissions and fuel efficiency. A 195-degree thermostat is perfectly fine for a stock daily driver and can provide better heater output in winter.
Pro Tip: There is no single 'correct' answer for all cars. If your Dart is stock and you live in a moderate climate, a 195°F thermostat is a good choice. If you have a modified V8 or live in a hot climate, a 180°F unit might be better.
Brand Quality & Tiers
Owner experiences from Mopar forums provide a good picture of brand quality.
- Standard Replacement (Good): Brands like Gates and Stant have a long-standing reputation for being reliable, standard replacement parts for classic Mopars. While some in the industry note that Stant is now owned by Motorad, they are still widely used and recommended.
- Standard Replacement (Economy): Motorad is a massive manufacturer that produces thermostats for many brands. Reviews are often mixed, with some reporting no issues and others experiencing early failures. They are a budget-friendly option but may lack the consistent quality of top-tier brands.
- Performance (Mixed Reviews): Brands like Mr. Gasket offer 'high-flow' thermostats designed for performance applications. However, owner reviews are very polarized. While some users are happy, there are numerous reports of these thermostats failing prematurely or even being non-functional out of the box. This makes them a higher-risk choice.
Before installation, it's a wise practice to test your new thermostat. Place it in a pot of water on the stove with a thermometer. Watch to see that it opens at its rated temperature (e.g., a 180°F stat should start opening around 180°F). This simple step can prevent you from installing a faulty part.
Known Issues, Recalls, or TSBs
There are no active recalls or Technical Service Bulletins (TSBs) from the NHTSA related to the engine coolant thermostat for the 1960-1978 Dodge Dart. Failures are typically due to normal age and wear of the part.
Frequently Asked Questions
Q: Can I just remove the thermostat?
A: No. Running without a thermostat will cause the engine to warm up very slowly and may never reach the proper operating temperature. This hurts fuel economy, increases engine wear, and can lead to the formation of sludge in the oil.
Q: What temperature thermostat is best for my Slant Six?
A: For most stock Slant Six engines, a 180°F or 195°F thermostat will work well. If you use the car for short trips, a 195°F stat will help the engine warm up faster and the heater work better.
Q: What about 'fail-safe' thermostats?
A: Some aftermarket thermostats are designed to lock in the open position if they fail. This prevents a catastrophic overheating event. While a good idea in theory, some owners report they can fail prematurely, leaving you with an engine that won't warm up. A quality standard thermostat is often the most reliable choice.
Q: How hard is it to replace the thermostat on my Dart?
A: On these classic cars, it's one of the easiest jobs you can do. It typically involves removing two bolts from the thermostat housing located where the upper radiator hose meets the engine.
Technical Specifications
Common temperature ratings are 180°F and 195°F. The correct choice depends on the engine (Slant Six, 318, 340, etc.) and model year. Always replace the thermostat housing gasket at the same time.
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.