How To Test The Engine Thermostat (1988-1993 2.8L Chevrolet S10 Pickup, GMC S15 Pickup, GMC Sonoma)

Engine Thermostat Basics

Who would of thought that despite its small size, the thermostat can cause so much havoc on the engine when it fails. For such an inexpensive cooling system component, it plays an outsized role in the engine's overall performance!

In case you're curious, here's a brief description of how the thermostat works:

• Cold engine start: When the engine is cold and has been turned off for a period of time, the coolant in the engine's cooling system is also cold.
• Closed thermostat: The thermostat is initially closed, preventing the flow of coolant from the engine into the radiator.
• Coolant circulation: As the engine begins to warm up, the coolant in the engine block absorbs heat from the engine components and expands.
• Temperature increase: The increase in coolant pressure and temperature causes the thermostat to open at 195 °F and allow coolant to circulate from the engine and into the radiator.
• Radiator flow: As the coolant circulates in the radiator, it's cooled by the air passing over the radiator fins. Since the thermostat is still in its open position, the cooler coolant now flows from the radiator into the engine.
• Engine cooling: As the cooler coolant circulates in the engine, it absorbs heat from the engine and cools it down.
• Thermostat response: As the temperature of the coolant continues to drop, the thermostat responds by closing and restricting the flow of coolant from the engine into the radiator.
• Temperature increase: With the thermostat closing, the coolant pressure and temperature (in the engine) begin to increase. At 195 °F, the thermostat opens and allows coolant to circulate from the engine and into the radiator.
• Wash, rinse, repeat: The thermostat will continuously cycle between opening and closing as the engine operates to maintain a consistent engine temperature, which helps to optimize fuel economy, reduce emissions, and ensure optimal engine performance.

More 2.8L Chevy S10 Pickup, GMC S15 Pickup, And GMC Sonoma Tutorials

You can find a complete list of tutorials for the 2.8L V6 Chevrolet S10 pickup, GMC S15 pickup, and GMC Sonoma in this index:

• GM 2.8L Index Of Articles.

Here's a sample of the articles, you'll find in the Index of Articles:

• How To Test The Fuel Pump (1988-1993 2.8L Chevrolet S10 Pickup, GMC S15 Pickup, GMC Sonoma).
• How To Test Engine Compression (1988-1993 2.8L Chevrolet S10 Pickup, GMC S15 Pickup, GMC Sonoma).
• How To Test The EGR Valve (1988-1993 2.8L Chevrolet S10 Pickup, GMC S15 Pickup, GMC Sonoma).
• How To Test The Starter Motor (1988-1993 2.8L V6 Chevrolet S10 Pickup, GMC S15 Pickup).