I have an 05 2.3 5-speed. Just yesterday at around 183k miles I noticed a knock relative to engine speed. It does not knock under load or at idle, it only knocks at very little throttle like when there is no vacuum or load. Oil was at the min mark on the dipstick (leaks alot) so I think it is rod knock.

generally when this happens on a vehicle with hi miles I pull the pan and replace the rod bearings to get by for a while.
I have been told it is unrebuildable and so far noone can sell me a rod bearing set. Does any one know why this is, or know where to get the bearings.

It still runs strong I just need it to get to about 230k or so. I am also annoyed that I wont be able to rebuild it myself and have to buy the complete short block (at rediculous cost)
Any help would be appreciated

 

Rod knock happens at any speed under any conditions.
What you describe sounds more like a valve train problem ,a rocker has come loose.

 

this is the DOHC 2.3 I didnt know it had rockers, but if it does then I'll gladly remove the valve cover to check for a loose one.
Also it still pulls smooth and knock free at WOT all the way to 5500 or so.
Would a loose rocker knock at idle - this one doesnt

 

I just checked it out and it is cam on tappet style valve train. No rockers

 

If it is knock free at 5500 it is not a rod .
One other thing I can think of is an exhaust manifold leak . That will sound like a knock.

 

will the exhaust manifold stop leaking under load and idle.
The best way to describe it is a knock while feathering the throttle

 

It may. You need to check the gasket between the manifold and head.
Look for signs of leakage , black soot around the ports.

 

Nope there is not the typical soot around the ports or under them.

Has anyone taken one of these DOHC 2.3's apart?

 

When was the timing belt last changed ? Could it be "slapping" and causing the noise ?

 

DOHC 2.3's have a timing chain.

I think I'll look elsewhere for engine technical advice

 

haha

PWNED!!

 

No offense intended.

 

Go to TheRangerStation.com. There are more people there, that know engines better than there are here.

 

You have no rockers hince DOHC cam on top of valves. It does sound like a valve taping. You need to check your valve clearence (distance between cam lobes and top of valves) and make sure they are still in spec. it is relatively cheap to replace the valve pads it just takes a lot of time, patience and math skills.