Ford Repair: water in oil, blown head gasket, water infiltration

Question
I have two question 1994 mercury grand mar 4.6 V8 120,00 mile never had a problem never lost water.

1. I had a rocker fall out of position. I replaced the hydraulic backlash adjuster and fixed the problem. What would cause this. Ford has no clue.

2. Second problem developed. Water in the oil big time. How common in a blown head gasket on this engine. Car never over heated.

The water line that goes under the intake manifold has a rubber hose connection. At the end of the valley there is an opening covered by a plastic cap. If the hose leaks can water enter the engine through this opening? I am in the process of pulling the heads but have no idea what causes the water infiltration or the head gasket to blow.  The car never over heated. Any information would be helpful.

I did drive the car about 10 mile with the rocker out of position ie. laying in the head. No obvious mechanical damage.

Answer
I cannot say whether or not the water is entering there. Either way, the intake is coming of at the very least. Hopefully, this will enable you to see a problem. If you do pull the heads, have them mic'd and checked. That hydraulic backlash adjuster is one of many. Keep this in mind and look for any defects or abnormalities.