I have been told that the rod bearings on my f150 4.6 are probably going out. The sound is heard right when the engine cranks over then disappears. While idling there is no fast knocking, but when revved to about 1700 rpm's the knocking comes back when the engine rpm's. The noise is there whether the truck is warm or cool.

If this is the case is it possible to pull the oil pan to replace the rod bearings? If so, does the engine need to be lifted some for access?


All thoughts are appretiated!

 

its possible, its just alot of work for taking a chance its not the bearing. If this helps you can get it to knock and pull the plug wires 1 at a time to find which one is knocking.

 

its best to pull the motor the front K memeber coversabout 90% of the pan

 

Thanks for the input. I'm going to try that this evening to see if helps reduce the noise. What other things could be causing this if I narrow it down to 1 cylinder?

 

If you've got damage to the rod bearings, the crank is probably hurt as well. Replacing only the bearings is like taking aspirin for a chainsaw wound.

 

piston pin, piston, bent rod, main bearing= old engine, low oil pressure

 

Yup if you're going to be that deep into it you might as well do all the bearings, maybe even need to have your crank turned?

 

Or a bandaid on a gunshot wound

 

That too.