Hello, this is my first post. Thanks for having me.

I purchased a 2002 Durango with the 4.7L late last week with a knocking noise. I assumed it was a hydraulic adjuster...and was wrong.

The vehicle has 98,000 miles on it with no sign of oil in coolant or coolant in oil.


My observations on the noise:

1. Sounds like it's coming from the passenger cylinder head.
2. Gets faster with more engine speed.
3. Knocks 90% of the time, but occasionally will cease or soften for a few seconds.
4. Makes the noise whether engine is cold or at operating temp.
5. Stops momentarily when I let off the gas and let the engine speed fall to idle from a mid range rpm. Resumes at normal idle rpm. (Guessing it stops because of reduced load)


My plan moving forward is to start the engine and unplug one coil at a time from that bank to see if I can make the noise almost go away. If I can, I'll swap a couple coils around to see if I can move the noise. Assuming that fails, I'll be dropping the oil pan and doing some rod wiggling to see if I can find a loose wrist pin.

My best guess is that it's a wrist pin based on where the noise is coming from, but I believe it's rare that those go bad. Not even sure how they would go bad. What causes that?

What are y'alls thoughts on this?

Video:

 

Hopefully you bought it for next to nothing, knowing that you may have to replace that engine. From the video, the knock sounds pretty heavy... almost like main bearings.

 

Have you checked the exhaust manifold bolts mine borke and it sort of sounded like that.