How to Replace the Thermostat on a 4.3 Silverado

by Zyon SilketUpdated November 07, 2017
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Items you will need

  • Front-end lift ramps

  • Wheel chuck

  • Drain pan

  • Pliers

  • Screwdriver

  • Thermostat

  • Thermostat gasket

  • Funnel

If you own a 2007 or 2008 Chevy Silverado with the 4.3-liter engine and the thermostat has gone bad, it is imperative that you replace the thermostat before it allows the engine to overheat and possible engine warping. The Silverado is capable of carrying large payloads that can put the engine cooling system under stress. But it's crucial to replace a failed thermostat even if you're riding empty. If your thermostat cannot regulate the amount of fluid going into the engine, you risk catastrophic engine failure.

Place the Silverado on a set of front-end lift ramps and secure the parking brake. Place a wheel chuck behind the rear wheel to keep the truck on the ramps. If you have a suspension lift kit installed on the vehicle, this step may not be necessary.

Drain the radiator fluid into a drain pan. To do so, remove the drain plug from the bottom of the radiator with a pair of pliers. Place the plug back into the radiator.

Locate the water inlet tube on the top of the Silverado engine by tracing the upper radiator hose. The hose extends from the radiator, then connects to the water inlet tube that is located on the intake manifold.

Remove the radiator hose from the water inlet tube using a screwdriver.

Remove the bolts that secure the water inlet tube to the intake manifold and then remove the water inlet tube from the intake manifold.

Pull the old thermostat out of the intake manifold and place the new one into the intake manifold. Half of the thermostat sits inside the intake manifold and the other half of the thermostat sits inside the water inlet tube. Place the thermostat into the intake manifold so that the end of the thermostat with the pin is sticking upward into the water inlet tube. This means the pin would face in the direction of the radiator and not the engine.

Pull the gasket off the intake manifold and replace it with a new one. Be sure that every bit of the old gasket is gone and all residue is removed from both the water inlet tube and he intake manifold so the new gasket will seal properly.

Place the water inlet tube back onto the intake manifold and secure it into place. Reconnect the radiator hose to the water inlet tube.

Drain the radiator fluid back into the radiator via the radiator filler cap.

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