Knocks at Idle Hot

^ Inspect the drive belt for wear. Check the tension and/or replace as necessary.
^ Inspect the A/C compressor or generator bearing. Replace or repair as necessary.
^ Inspect the valve train. Replace the parts as necessary.
^ Inspect for improper oil viscosity. Install proper viscosity oil for expected temperature.
^ Inspect for excessive piston pin clearance. Replace the piston and pin as necessary.
^ Inspect the connecting rod alignment. Check and replace the rods as necessary.
^ Inspect for insufficient piston to bore clearance. Hone the bore and fit the new piston.
^ Inspect the crankshaft balancer for looseness. Torque and/or replace the worn parts.
^ Ensure that the piston pin is not offset to the wrong side. Install the correct piston.
^ Ensure that the camshaft drive gear backlash is not excessive. Knock will also be heard on a cold engine.