How To Test The Thermostat (1993-1996 2.2L Buick Century, Oldsmobile Cutlass Ciera)

Engine Thermostat Basics

The engine coolant thermostat is a critical component of the engine management system on your 2.2L Buick Century or 2.2L Oldsmobile Cutlass Ciera.

This all boils down to the fact that the colder the engine is, the more fuel it needs to stay running.

As the engine reaches its normal operating temperature, it needs less fuel to run. And since less fuel is required to keep the engine running, it produces less hydrocarbon emissions.

In a nutshell, the thermostat helps regulate the engine's temperature so it can perform optimally and produce less emissions.

Here are some more details:

1. When you start your vehicle's engine:
   • The thermostat is closed.
   • The radiator fan is OFF.
2. As the engine coolant circulates in the engine only, its temperature increases, and when it reaches 195° F, the thermostat opens.
3. The hot coolant now circulates between the radiator and the engine with the thermostat open.
4. Even tho' the thermostat has opened, the temperature of the coolant will continue to increase.
5. All the while, the engine coolant temperature is continually monitored and reported to the fuel injection computer by the engine coolant temperature (ECT) sensor.
6. When the computer sees the ECT sensor reporting a temperature of around 220° F, it commands the radiator fan ON.
7. The engaged fan now pulls more air across the radiator, cooling the coolant within it.
8. Since the thermostat is open, the cooler coolant in the radiator enters the engine to cool it down.
9. As the coolant's temperature decreases further, the fan is commanded OFF, and the thermostat closes.
10. The coolant in the engine now begins to absorb more heat, and the process repeats itself continually the whole time the engine is running.

More 2.2L Buick Century And Oldsmobile Cutlass Ciera Test Tutorials

If this tutorial was helpful, be sure and take a look at all of the 2.2L Buick Century and Oldsmobile Cutlass Ciera diagnostic tutorials in this index:

• GM 2.2L Index Of Articles.

Here's a sample of the tutorials you'll find there:

• How To Test The Fuel Pump (1993-1996 2.2L Buick Century, Oldsmobile Cutlass Ciera).
• How To Test The TPS (1993-1996 2.2L Buick Century, Oldsmobile Cutlass Ciera).
• How To Test Engine Compression (1993-1996 2.2L Buick Century, Oldsmobile Cutlass Ciera).
• How To Test The MAP Sensor (1993-1996 2.2L Buick Century, Oldsmobile Cutlass Ciera).