4.0 Short Block Replacement

[LegacyL22]

I made a post a few weeks ago, because my oil pressure was extremely low at idle. I thought it was a spun bearing, but i don't know enough about that to properly diagnose it. It runs fine, i have driven it probably a few hundred miles, because I have to move stuff, but it still has a knocking that sounds like a woodpecker at around 2k - 2500rpm under load, and at idle there is a slight noise that sounds like a piece of metal tumbling around in the oil pan. pressure is about 40psi at 2k, but thats with 20w50. My question is, does it sound like a spun bearking? and would anyone recommend replacing the short block. I love the truck, but i don't want to risk spending a whole bunch of money and not have it be fixed. Thanks

 

[MAKG]

If you're sure the sounds are coming from the oil pan, you probably need a short block.

But pull the engine, remove the oil pan, and inspect it. You can inspect half of every bearing that way. If it's spun, you'll know. Measure oil clearances if there isn't anything obvious.

But make DANG sure it isn't detonation. You may just need a $20 gasket, or even less....

Detonation is generally described as marbles in a tin can. It doesn't sound like detonation from your description, but it's very much worth ruling it out.

And remove the heads BEFORE buying a short block, as you may discover you really need a long block....

 

[shadetree]

My question is, does it sound like a spun bearking? and would anyone recommend replacing the short block. I love the truck, but i don't want to risk spending a whole bunch of money and not have it be fixed. Thanks

Nope. If you had a spun bearing, the engine would be toast by now. A spun bearing won't last a few hundred miles. A remote possibility is a loose converter, or flywheel/flexplate. shady