I may need to add this to my Blog but oil never bleeds out of a lifter when the engine is off.
They do bleed down but the oil just goes back into the top reservoir area of the lifter.
The first time the valve closes for that lifter the spring in the bottom of that lifter pushes the plunger back up and oil is drawn through the check valve back into the working area and the lifter is ready to go.
If they click on startup it is because the plunger gets stuck in the bottom of the body after they bleed down while the engine is off and cools. As the lifter warms the body expands more than the plunger and releases the plunger and the lifter starts working correctly. This can happen with new lifters where the plunger is too tight in the body, and it can happen on old lifters that have gummed up internally.
If it is happening with new lifters they will wear in after some wear in time and work correctly.
Last edited by Pre '68 Dave; 07/01/2013 6:30 PM.
