Oil Pressure Problem?

Only one way to tell, perform a pressure test.

The lifters could be a little gummed up. it sounds like the lifters are not holding pressure, this is nothing to be allarmed about as long as the tapping stops after a short time and there are no other knocking sounds. When the engine starts it pumps the lifter back up , then the tapping stops. I have a subaru with 137,000 miles on it. I installed a manual pressure guage. When i start the subaru it sounds like a bunch of marbles in it, after running about 5 minutes the sound gets less and less until it stops. I am running 70 pounds of oil pressure. You can add a can of lucas oil or something like stp to keep the engine lubed when you shut it off, so you don't have a dry start. {when all the oil has drained back into the pan} If they get too loud I would have the lifters checked and adjusted.