Where is the radiator drain plug located on a 2000 GMC Sierra Classic 1500?

Answer 1

The radiator drain on a 1995 - 2000 GMC Sierra 1500 Classic pick-up truck is located at the inside bottom left corner of the radiator (driver's side facing the wheel). It is difficult to access due to the front metal wheel well guard (using hands to slightly bend - an inch or so out - the lower inside front corner into the wheel well provides a little better access without removing any bolts & you can bend it back later to its original position). The radiator drain petcock is plastic with a plastic turning blade. You will need a narrow diameter petcock tool to open this as it tends to stick if not opened/closed for a couple years and there in almost no room to use your fingers. (I made a quick "tool" out of a 10 inch long piece of 1/2" thick-wall PVC by cutting a 3/16" wide by 1/2" deep notch into one end, drilled two 1/8" thru holes at 90 degrees to each other thru the opposite end and used a nail in these holes for leverage to turn the "tool" - saved $12+ and a 30 mile trip to the parts store). The petcock needs to be turned approximately 90 - 120 degreescounterclockwise to pop out and open (do not force further counterclockwise or you may break the petcock!). The contents of the radiator will run onto the frame due to GMC's poor engineering) and drip from several places, so have additional buckets ready to chase the mess. (The draining process was relatively slow, taking about 10 minutes to drain 8.2 quarts of old fluid, so be patient!). Often Overlooked: Don't forget to remove the old antifreeze mix from the overflow reservoir (on the passenger side firewall). Carefully remove the overflow hose from the radiator at the radiator cap and lower it below the reservoir tank to drain it.