Engine Coolant Thermostat Replacement for the 1989-1990 Dodge 2000 GTX
Your guide to keeping the 2.0L engine in your Canadian-market Mitsubishi Galant twin running cool.
- Your Dodge 2000 GTX is a rebadged Mitsubishi Galant; parts for the 1989-1990 Galant 2.0L will fit.
- A stuck-closed thermostat will cause rapid overheating and can destroy your engine; pull over immediately if the temperature gauge spikes.
- The correct OEM temperature is 180°F (82°C); do not use a thermostat with a different rating.
- Aftermarket quality varies; Calorstat and Gates are generally reliable choices, while Motorad has more mixed reviews.
Understanding Thermostat Failure in Your 2000 GTX
The thermostat in your 1989-1990 Dodge 2000 GTX is a simple mechanical part that can fail in two main ways. Since your car is a rebadged Mitsubishi Galant with a 2.0L 4G63 engine, information for those cars applies directly to yours. No recalls or Technical Service Bulletins (TSBs) for thermostat failure have been issued by Dodge or Mitsubishi for this specific model, indicating failures are due to age and wear rather than a design defect.
Stuck Closed: High Risk of Overheating
This is the most common and most dangerous type of failure. The thermostat gets stuck in the closed position, blocking coolant from reaching the radiator. This will cause the engine to overheat very quickly, which can lead to warped cylinder heads, blown head gaskets, and catastrophic engine damage. If you see the temperature gauge shoot into the red, pull over and shut off the engine immediately.
Stuck Open: Engine Runs Too Cool
A thermostat stuck in the open position allows coolant to circulate constantly, even when the engine is cold. This prevents the engine from reaching its ideal operating temperature. You'll notice the temperature gauge stays low, your heater doesn't blow hot air, and your fuel mileage gets worse. While not immediately damaging like overheating, it causes increased engine wear and poor performance over time.
Choosing the Right Aftermarket Thermostat
For a vehicle of this age, you don't need to hunt down a rare OEM part unless you're doing a museum-quality restoration. Aftermarket brands offer good quality, but there are differences. The most important thing is to get a thermostat with the correct temperature rating.
| Vehicle | 1989-1990 Dodge 2000 GTX (2.0L SOHC/DOHC) |
| OEM Opening Temperature | 180°F / 82°C |
Pro Tip: Always replace the thermostat gasket or O-ring when you replace the thermostat to prevent leaks. Many thermostats come with a new one in the box.
Brand Quality Tiers
- Good Quality (Recommended): Brands like Gates and Calorstat have a generally positive reputation. Gates is a well-known aftermarket supplier for many parts. Calorstat is a respected OEM supplier for many European brands and is often recommended on forums.
- Standard/Budget Quality: Motorad is a very common aftermarket brand, but user reviews are mixed. While many have no issues, a notable number of mechanics and DIYers report problems with them failing prematurely or not regulating temperature correctly. Some users also report that other brands, like Gates, may sometimes re-box Motorad parts.
Frequently Asked Questions (FAQ)
Can I use a thermostat with a different temperature rating?
It is not recommended. The 2.0L engine was designed to run with a 180°F (82°C) thermostat. Using a lower temperature thermostat will cause the engine to run too cool, hurting fuel economy and performance. Using a higher temperature one increases the risk of overheating.
What is a "fail-safe" thermostat?
A fail-safe thermostat is designed to lock in the open position if it fails. This prevents a catastrophic engine overheat by allowing coolant to continue flowing. While it sounds good, many mechanics prefer the simplicity and proven design of a high-quality standard thermostat.
Is replacing the thermostat a DIY job?
Yes, for most home mechanics with basic tools, this is a very manageable job. The thermostat on the 4G63 engine is typically easy to access. The process involves partially draining the coolant, unbolting the housing, swapping the part, and then refilling and bleeding the air from the cooling system.
Why is my heater blowing cold air?
If your heater is blowing cold or lukewarm air, it's a classic symptom of a thermostat that is stuck open. The engine isn't getting hot enough to provide hot coolant to the heater core inside your dashboard.
Technical Specifications
OEM Part Numbers: MD997606 MD972903
Opening Temperature: 180°F (82°C)
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 2000 GTX: