Jumped Timing Chain?

[James Bowers]

I have a 2004 Explorer Sport Trac 4.0/5 speed auto with 68k miles.

It started running rough the other day and when a fuel filter replacement didn't resolve the issue I had it towed home. Next morning I ran the codes but I think the codes were due to me forgetting to plug the mass air flow sensor in when I checked the condition of the filter.

I started it up after clearing the codes, it was running rough and then I heard a noise that was not good to anybody with any familiarity with engines. It sounded like something came into contact with a moving part. I shut it off right away and when I tried to restart it something is stopping the engine from turning over. I am able to put a socket on the crankshaft bolt and back it up, but moving it forward it comes to a hard stop.

Did I loose a tensioner and it is jammed somewhere?
Did the chain skip and that is why it ran rough?
Or is there a valve hitting the piston? Is this an interference engine?

I can't believe at only 68k miles this thing let go. I'm assuming that if it has anything to do with the cams I need to pull the engine? Maybe it's just the front tensioner and the rear guides are ok?

Thoughts?

 

[CDW6212R]

Welcome James, and sorry to hear of the problem. It's easiest to pull the valve covers to see if anything is visible from the top first. Then to remove the timing cover to look is a much bigger job, everything has to come off of the front of the engine to get that cover off. Chances are something in the valvetrain is out of place, broken and/or jammed into the rest of the timing chain parts, which in 95% of cases will mean re-timing the chains, plus parts etc. Hopefully that's all it is, if no hard damage is done to the rest of the engine, it can be just the timing components, and the re-timing of all of them.

Search here for many threads about the SOHC 4.0 V6's, the timing cassettes and tensioners. The pictures will explain a lot of it.