A Guide to the Engine Coolant Thermostat for the 1983-1992 Isuzu Impulse
Understand the signs of a failing thermostat in your Impulse and how to select the best new aftermarket replacement.
- A thermostat failing 'stuck closed' causes critical overheating; 'stuck open' causes the engine to run too cool and the heater not to work.
- For this vehicle, a quality aftermarket thermostat from a brand like Gates or Stant is a reliable and cost-effective choice.
- Always replace the thermostat gasket at the same time to prevent coolant leaks.
- The correct thermostat for most Impulses is rated to open at 180°F (82°C).
Symptoms of a Failing Thermostat in Your Impulse
A thermostat can fail in two ways: stuck open or stuck closed. Each has its own set of distinct symptoms.
Stuck Closed: Engine Overheats
This is the more serious failure. When the thermostat is stuck closed, it never opens to let hot coolant get to the radiator. Symptoms include:
- Temperature gauge quickly rising into the red zone.
- Engine overheating, which can cause serious damage like a warped cylinder head.
- Coolant boiling over or leaking from the pressure cap.
- Gurgling or knocking sounds coming from the engine area.
If you suspect your thermostat is stuck closed, pull over and shut off the engine immediately to prevent catastrophic damage.
Stuck Open: Engine Runs Too Cool
A thermostat stuck open allows coolant to circulate constantly, preventing the engine from ever reaching its proper operating temperature. This is less critical but still needs to be addressed.
- The temperature gauge stays low or takes a very long time to reach the normal range.
- Your cabin heater blows lukewarm or cold air, even when the engine has been running for a while.
- A noticeable decrease in fuel economy, as the engine runs inefficiently.
Choosing the Right Aftermarket Thermostat
For a vehicle like the 1983-1992 Isuzu Impulse, a quality aftermarket thermostat is a perfectly reliable and cost-effective choice. OEM parts can be difficult to find and may not offer a significant advantage for this component. Here’s a breakdown of common aftermarket brands.
Pro Tip: Most thermostats for the Isuzu Impulse are designed to open at 180°F (82°C). Always verify the correct temperature for your specific engine and model year before purchasing.
Brand Quality Tiers
- Tier 1 - Trusted Aftermarket (Gates, Stant): Gates and Stant have long been trusted names in cooling system parts. They are generally considered reliable, go-to options for a standard replacement. Some forum users note that Stant's quality has changed since being acquired by Motorad, but they remain a popular choice.
- Tier 2 - Good Value (Motorad, Beck Arnley): Motorad offers good value and some of their product lines are well-regarded for stable temperature control. However, reviews can be mixed, with some users reporting premature failures. Beck Arnley specializes in parts for foreign nameplates and aims for OE-matching quality, often by repackaging parts from various manufacturers. This can lead to inconsistent quality, with some parts being excellent and others failing early.
- Other Brands (Facet, Calorstat): These brands are also available but have less feedback in North American forums compared to the others. They can be a suitable budget option if higher-tier brands are unavailable.
Aftermarket Thermostat Replacement Cost for Isuzu Impulse
Replacing the thermostat is one of the more affordable repairs. The part itself is inexpensive, and labor is straightforward for a mechanic. Below are typical cost ranges you can expect.
| Part/Service | Estimated Cost |
|---|---|
| New Aftermarket Thermostat | $8 - $25 |
| Shop Labor | $62 - $91 |
| Total Professional Replacement | $70 - $116 |
Note: Costs are estimates and do not include taxes, fees, or the price of new coolant. RepairPal shows a much higher average total cost of $320-$349, which may factor in a complete cooling system flush or other services.
Frequently Asked Questions
What temperature thermostat does my Isuzu Impulse need?
Most 1983-1992 Isuzu Impulse models use a thermostat rated for 180°F (82°C). This is the standard temperature required for the engine to operate efficiently. Using a thermostat with a different temperature rating is not recommended.
Should I replace the thermostat gasket at the same time?
Yes, absolutely. The gasket seals the thermostat housing to prevent coolant leaks. Never reuse an old gasket. Many new thermostats come packaged with a new gasket, but if not, be sure to purchase one separately.
Is an OEM Isuzu thermostat better than aftermarket?
While OEM parts are always a safe bet, they can be hard to find and more expensive for a vehicle of this age. For a simple component like a thermostat, a quality aftermarket brand like Gates or Stant is widely considered to be a reliable and perfectly acceptable alternative.
What other parts should I inspect when replacing the thermostat?
While you're working on the cooling system, it's a good time to inspect the radiator hoses for cracks, swelling, or softness. Also, check the coolant level and condition. If the coolant looks rusty or dirty, it's a good idea to perform a full system flush.
Technical Specifications
OEM Part Numbers: 8943360690 8941718160 8942072171 8942072172
Standard Temperature: 180°F (82°C)
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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.
- Isuzu Impulse: