My '08 F150 5.4 3V had a intake rocker arm kicked out on #4 cylinder , trucks only got 120,000 km ,motors clean like new inside ,rollers wore and feels rough , How common is this ? it's my sunday going to church truck ! Got a Quote of $4000 to fix !! retainer and valve spring is off the intake valve and it appears to bee about 1/4" down and stuck!!
Frank

 

Not real common but it happens. Normally they make a ticking noise for a while before getting thrown off the valve. If the valve is stuck then it hit the piston and you will need a cylinder head due to the valve guide breaking. I have seen the aftermath of them going at highway speed and the valve stem is punched through the intake port and the head of the valve is laying in the oil pan along with pieces of piston.

 

complete timing job replaced all rollers and lash's . I blame the lash's and combustion dirt jamming them up . At that price I would do reman . If you do it yourself it may be worth it but depending on miles maybe not . . Need to scope piston to see what damage . I now run marvel m oil to help clean it .
A new head would be pricey ,I have no idea how much with cam and all .