A friend of mine took his 03 Durango to the dealer because it was running really bad. They said compression was bad and it would be $9K to swap out the long block. I told him we could swap it out for a lot less.

Before we just pulled the engine I decided to check it out. Compression was good on all but #2 and #8 cylinders. Pulled the valve cover and found two rocker arms sitting there loose.

I don't know much about OHC engines. What would cause the arms to fall out? Should I pull the head to inspect the valves or will a leakdown test be enough? Has anyone else had this happen?


Thanks!


Jason

 

on the 4.7, the used engine is about $2000+ and reman(jasper) is about $5000+
i have done a few motor swap cause by electric fan quit working and over heated motor or sprun rod bearing.
i know that the labor for job like that is about 14+ hours. it took me about 8 hours to swap.

but if its just couple rocker fell out, pull the head to make sure nothing is wrong with the cyl/block/piston. patriot make replacement cyl head.. you will need special tool to hold the timing chain.
hopefully cam is good or just replace it. also make sure the cam sensor don't have metal on it(pass side cyl head)

 

btw, is the rocker just came loose and fell off??? or something hold the rocker broke (ex:cyl head?)

 

The rocker just came off. I talked to a mechanic at the dealership and he said he had seen a few lifters fail and cause the same thing. This makes sense to me. I came back home and hooked up an air hose to the cylinders in question and the both held air. Valves sealed fine. Valve springs all appear to be fine.


Soo.....I think we are going to try and replace the lifters and see what happens. There was all kinds of sludge in there so maybe that caused a lifter to die?

 

maybe, i know any motor hate sludge!!!

tell your friend change oil often!!!

 

Lol! He'll get a lecture. Along with some advice......to trade it in.

 

Found the culprit. Two of the valves (and seats) were sitting about 1/4" down in the head. Not far enough to hit the piston though. With the slack...the rocker arms came loose and were just spit out by the cam. Weird....never saw that before.

 

they had a problem with the earlier 4.7's. the valve seats would pop off.