MY 1999 Ranger 4.0 OHV engine just started making a strange tapping sound. Seems to be coming from the alternator mounting on top of the left cylinder bank but it's inside the engine. Removed the rocker cover and valves and clearances all seem good. Noise not always there and it changes from a tapping to sounding like something slapping around loose inside.
Oil pressure is good and the truck idles fine but it sounds terrible. Started tonight and virtually no noise at first. A little bit of throttle made the noise come back almost immediately. I removed the serpentine belt to isolate the noise and definitely inside top left cylinder bank.