Q: How do you remove and reinstall Pushrod and Rocker Arm in V8 engine on Chevrolet Colorado?
A: To remove the valve covers from the cylinder heads, first loosen the rocker arm pivot bolts one at a time and take out the rocker arms and bolts, followed by the pivot support pedestal, ensuring to keep track of the component positions for reinstallation. Store each set of components separately in marked containers to maintain their original locations, including the rocker arms and pivot support. Next, remove the pushrods and store them in order to avoid mixing them up during installation. Inspect each rocker arm for wear, cracks, and damage, particularly at the contact points with the pushrods and valve stems, and check the pivot bearings for binding and roughness; if worn or damaged, the entire rocker arm will need replacement. Ensure the hole at the pushrod end of each rocker arm is clear, and inspect the pushrods for cracks and excessive wear, checking that the oil hole is not clogged and rolling each pushrod across a piece of plate glass to detect any bends. For installation, lubricate the lower end of each pushrod with clean engine oil or assembly lube and install them in their original locations, ensuring each pushrod seats completely in the lifter socket. Apply engine assembly lube to the ends of the valve stems and upper ends of the pushrods to prevent damage during initial start-up, and also apply clean engine oil to the pivot shaft and bearing of each rocker arm before loosely installing the rocker arms in their original locations without tightening the bolts. Rotate the crankshaft until the number one piston is at TDC on the compression stroke, ensuring both pushrods for the number one cylinder are in the lowered position, then tighten the intake valve rocker arms for cylinders 1, 3, 4, and 5, and the exhaust rocker arms for cylinders 1, 2, 7, and 8, to the specified torque. Rotate the crankshaft 360 degrees and tighten the intake valve rocker arms for cylinders 2, 6, 7, and 8, and the exhaust rocker arms for cylinders 3, 4, 5, and 6, to the specified torque. Finally, install the valve covers, start the engine, and listen for unusual valve train noises while checking for oil leaks at the valve cover gaskets.