Looking for some education from my FTE family. A friends 2005 F150 5.4L Auto 4X4 trucks engine died at 125,000 miles. He was on the freeway driving home and truck stopped operating. The truck was towed to a local independent shop that we have used, with good service in the past. The analysis came back that he needed a new engine 7 to 8K. For a second opinion it was towed to the Ford Dealership the first test came back cam phasers but final dealership analysis was also needs new engine. I speak points and push rods (old man). Can someone please explain how an engine goes from a good running, no oil burning engine to needs new all at once in a truck that has been trouble free?
Thanks

 

I'm going to take a guess, but in some cases on these overhead cam engines, a few have been known to jump time (maybe from a stretched chain or broken chain guide, failing tensioner, etc) and in the case of these 5.4L engines (valves interfere with the pistons if out of time) end up smacking the valve, breaking the rocker arm, valve spring, keeper, denting or even cracking the piston, etc.

Another thing that comes to mind is it may have had a rocker arm roller bearing failure. In this case, the cam lobe rides on the roller and pushes down on it - sometimes these rollers have been known to seize and cause the cam lobe to begin dragging on the roller. This is usually noticeable though with a ticking noise, or knock. Over time, it can eventually break the rocker arm and in the process break the valve keeper and then the valve drops into the cylinder with lots of carnage in the cylinder (usually). Definitely wouldn't be the first time this has happened.

 

Thanks for the reply. This helps and also explains why some refer to the new engines as mouse trappy. Well I hope my 2004 5.4L keeps running for many more years.