99-13 Chevy Silverado 4.3 Vortec Thermostat Change Replacement How to Replace

Introduction

This tutorial provides a step-by-step guide on how to change the thermostat in a 1999 to 2013 Chevrolet Silverado equipped with the 4.3 V6 Vortec engine. This process is similar for other vehicles with the same engine, such as the S10, Sonoma, Blazer, Jimmy, and Astro. Replacing the thermostat is an essential maintenance task that ensures your engine operates at the correct temperature, preventing overheating and other issues.

Step 1: Gather Necessary Tools and Materials

Before starting the replacement, ensure you have the following tools and materials ready:

• Half-inch wrench
• Flathead screwdriver (optional)
• Rag or cloth for soaking up coolant
• New thermostat with rubber gasket (pre-installed is recommended)
• Coolant for topping off

Step 2: Safety Precautions

• Ensure the vehicle is cool before starting the work to avoid burns from hot components.
• Work in a well-ventilated area and consider using jack stands for safety if the vehicle is lifted.

Step 3: Locate the Thermostat Housing

• Identify the thermostat housing, which is typically located near the engine block.
• Note that there are two bolts securing the thermostat cap.

Step 4: Remove the Thermostat Housing Cap

• Use the half-inch wrench to remove the two bolts.
• Expect some coolant to spill out when you remove the cap. Be prepared with a rag to catch any fluid.
• If space is tight, consider using a shorter wrench or a socket with an appropriate extension.

Step 5: Clean the Mounting Surface

• After removing the old thermostat, inspect the area where it sits.
• Use a rag to soak up any remaining coolant and dry the mating surface to ensure a clean seal for the new thermostat.
• Make sure the area is free of old gasket material and dirt.

Step 6: Install the New Thermostat

• Place the new thermostat in the housing, ensuring the rubber gasket is seated properly.
• If the gasket is not pre-installed, take care to place it correctly without any twists or gaps.

Step 7: Reattach the Thermostat Housing Cap

• Carefully position the thermostat housing cap back into place.
• Tighten the bolts snugly. While the torque specification is 21 foot-pounds, a snug fit is generally sufficient for this application.

Step 8: Refill Coolant and Check for Air Bubbles

• Refill the coolant directly into the thermostat housing, as there is no traditional radiator cap on these vehicles.
• Start the engine and let it reach operating temperature, which helps to circulate the coolant and remove air bubbles from the system.

Step 9: Monitor Engine Temperature

• Allow the engine to run for a few minutes to ensure it does not overheat.
• Keep an eye on the temperature gauge and don't stray too far from home during this initial test.

Conclusion

Changing the thermostat in your Chevrolet Silverado is a straightforward process that can help maintain your vehicle's optimal performance. Remember to give the new thermostat a heat cycle followed by a cool-down cycle before pushing the engine hard. If you encounter difficulties, consult a professional mechanic for assistance. Regular maintenance like this can enhance your vehicle's longevity and reliability.