How do you drain antifreeze from 2006 3.9 Chevy Impala?

Answer 1

Remove plug or open petcock at lower or rear of radiator or remove lower radiator hose. This removes a bit over 4 quarts of the 12 quart system total. The remainder is in the block. The thermostat is in the fitting where the lower hose connects to the block. Removing the hose clamp and removing the two bolts to remove the thermostat allows almost another quart to drain which means you still have a little over 6 quarts in the block.

There are two block drain plugs but on the '06 Impala they are very difficult to get too. One is at the front of the block very near the oil filter...just above and to the passenger side. The other plug is for the rear bank and is located almost in the symmetrical opposite at the rear of the engine. The transmission makes this one impossible to get to from below but if you have someone looking from below, you can remove the coolant reservoir tank and reach around from the rear passenger side of the block with a wrench to remove this plug. This is all time consuming and difficult because you want to be able to remove all of the coolant flush and then flush with tap water followed by total removal of the tap water and then installation of the distilled water-dexcool 50/50 solution. It is much easier to take it to a shop and have them use the coolant exchange machine to perform a thorough "flush and fill" procedure. Hope this helps you