My friend has a 2005 Chevrolet Blazer with the optional ZR2 wide-stance package. It's a nice truck. It has the 4.3-liter V-6 engine. When it started overheating, he gave me a call to help him replace the thermostat. We put the floor jack in the center under the front crossmember and then put jack stands under the frame rails behind the front wheels. When we reinstalled the drain plug, we tightened it to 18 inch-pounds.
To get to the thermostat housing, we had to remove the air cleaner outlet duct and throttle body bracket nuts, and move the bracket out of the way. On reassembly, we tightened the thermostat housing bolts to 14 foot-pounds and the throttle body bracket nuts to 89 inch-pounds. The cooling system bleeder screws had to be opened before refilling the system with a 50 percent solution of Dex-Cool antifreeze and drinking water, and then closed before starting the engine.
