I have a 08 Chevrolet Impala with a 3.5 with 70k miles. There is a tick that corresponds to engine speed. It's a pronounced tick but I highly doubt its piston slap or rod knock. It seemed like an exact match for a noisy lifter. I replaced lifters and same thing.
The noise seems to come from the upper part of the motor, maybe slightly to the rear, below the plenum. Oil level is fine and no low oil pressure light.
What else could cause engine tick?
Video may tell more
Touching the crank, feels smooth. Nothing like the rod bearing. Need to mic it though.
UPDATE 2 : Several rod bearings are similar to this but not quite as bad. Main bearings are fine. What could have caused this?