The crankcase on this engine is under vacuum rather than postive pressure. That means it has NCV(Negative Crankcase Ventilation) instead of PCV(Positive Crankcase Ventilation) which results in no ventilation at all. Instead of having one hose supplying air to the valve cover on one bank and another hose from the other valve cover feeding blowby from the crankcase to the intake manifold as the other brands do this engine has hoses running to the intake manifold from BOTH banks putting the oil pan under vacuum which is OK if air can get in to the crankcase from somewhere else. I'm guessing the air inlet is clogged or blocked causing a vacuum in the crankcase. If you pull the dipstick out with the engine running and put your finger over the dipstick tube your finger is held fast to the tube by vacuum. Where is this air inlet for the 5.4 3 valve V8 located?

 

sorry to burst your bubble but a 3v has a pcv system, the valve is on the passenger side valve cover

 

On the 5.4 3 valve the hose on the passenger side(Bank1) is routed just like the hose on the drivers side(Bank2). Both hoses go directly from the valve covers to the intake manifold with Bank2 having a PCV valve built into the valve cover. The difference with other engines is that the passenger side hose doesn't connect to the intake manifold, but rather to a bung on the intake plenum between the air filter and the throttlebody. This means air comes in to the Bank1 and heads to the crankcase and finally exits through Bank2 via a hose leading to the intake manifold through the PCV valve on the Bank2 valve cover. The air in the system travels in a loop so the crankcase is constantly ventilated. The 5.4 3 valve doesn't appear to use this loop type system. Since the Bank1 hose on the 5.3 3 V8 valve cover conects to the intake manifold the air inlet has to be located somewhere else.

 

well I don't have a 3v in front of me right now to look at, however to answer your question about a vac coming from your dip stick that is normal, if you look at a source of vac leaks the shop manual lists that

 

This truck belongs to a friend which he bought used. It has 225K on the clock. Maybe the hose on Bank1 is routed incorrectly.