On my 2001 Ford Ranger 4.0 SOHC all of a sudden I hear a knocking from the valve cover on the passenger side. I have heard the you tube videos of timing chain noise but this us a knock like something is actually hitting my valve cover. I found one like of a you tube post that has the exact same knock but there isn't a solution. Can some watch this you tube video and see if you can recognize the knock. If I raise the RMP is goes away its only a low idle that it knocks and just started today.

 

Doesn't sound to healthy, bummer.

Under the exhaust manifold near the rear on that side is a hydraulic tensioner for the timing chain, large hex bolt head on it, check to see if it is loose, or even unscrew it and pull it out to see what the end looks like.

This is what it looks like:
Other wise I would not drive it and at least pull the valve cover on that side.

If engine is cold you can remove fan belt and run engine for 1 to 3 minutes without water pump/fan turning, this reduces noise in engine bay so you can pin point a noise easier.

 

Sounds like timing chain to me. Mine had the same symptoms and finally pulled it apart to find the guide destroyed. Very common issue with '01-03' SOHC motors.

 

Thanks for the reply. The noise "knocking" has stopped. I am going to look into replacing the timing chain tensioners soon.

 

It came back and I took the valve cover off and seen the plastic timing tensioner cartridge in the rear was broken and bouncing around. Thank god it didn't slip time. Its in the shop now replacing with a new timing kit front and rear. $1500.00 including labor other shops wanted $3500.00.