How to Flush a Radiator on a Chevy Tahoeby Chris Moore
You need to flush out the radiator on your Chevy Tahoe truck every 30,000 miles or 2 1/2 years, whichever occurs sooner. Flushing the radiator and adding fresh coolant will help prevent rust and corrosion from building up in the cooling system.
Make sure the engine is cool. Wait at least three hours after last driving the vehicle or perform this maintenance before driving it at all on a particular day. Apply the truck's parking brake and block the front wheels.
Drain the engine coolant. Place a large, clean container under the radiator drain on the radiator's lower left side, pull out the rubber drain hose from its support, aim it into the container and open the drain fitting with pliers. Once the coolant is drained from the radiator, move the container to the engine block's drain plugs and remove the plugs to drain the remaining coolant.
Remove the thermostat from the engine. With the battery's negative cable disconnected, remove the air filter housing and intake duct, then find the thermostat at the engine front on the lower intake manifold. Detach the radiator hose from the thermostat housing by loosening its clamp, remove the cover's bolts/nuts with a wrench to remove the cover and remove the thermostat from the cover.
Reinstall the thermostat housing by itself, along with the hoses and plugs you drained the coolant from. Turn the vehicle's heating controls to "hot."
Disconnect the upper radiator hose and insert a garden hose into the opened inlet. Run the hose water through the radiator until clear water runs out of the radiator hose you just disconnected.
Reinstall the radiator hose and the thermostat, then turn the heater control to the maximum position. Refill the coolant surge tank with a 50/50 mixture of coolant and demineralized water, filling it to the tank's "fill cold" mark.
Start the Tahoe's engine with the coolant tank's cap still off and let the engine idle for about a minute. Put the cap back on without tightening it and run the engine up to 3,000 RPM every 30 seconds until it reaches its normal operating temperature.
Shut off the engine and remove the coolant tank cap. Restart the engine, let it idle for another minute and add more coolant to a half inch over the "fill cold" mark. Repeat the above-mentioned RPM cycles and shut the engine off after it reaches normal temperature. Refill the tank until it's a half-inch over the "fill cold" line again and securely close the cap.