Ok so the old Hoe has 165k on it. On cold start up one of the lifters is slow to pump up but does after about 3 to 4 seconds. Oil pressure is good at start up. jumps right up to 50 to 60 psi. It never does it after start up. Not at stop lights on hot days, not after sitting for a couple of hours. Only does it in the morning on cold start up. Should I be worried? do I need to start figuring out which one and replace it or just replace them all? I have no current plans to rebuild this thing any time soon. Just need it to keep on trucking.