Recently I started hearing a loud tapping sound coming from the engine of my 95 PSD. After checking everything I could think of I finally discovered a loose rocker arm under my passenger side valve cover. Its not seriously loose just a lot of play in it in when its not under load. I removed it and checked for damage or a bent pushrod but nothing..... I dont see anyway where it can be adjusted and my question is just how do you adjust the tension on the rocker arms??
and if not adjustable what could cause it to be loose? .......HELP!!

 

The rocker is probably broke, cracked or stretched. I would look it over closely. Maybe even remove another and compare them side by side.

 

Lifter bleeding down.

Bill