Once again, I disagree. If everything is the way it's supposed to be, the 4.0 is a very smooth, quiet engine that is engineered well. Probably one of the better designs to come from anyone you care to name. It develops a lot of power for its size. It also tends to last a long time with normal maintenance.

The clattering was not designed in.

 

I agree Firestorm, but the fact remains that they DO rattle but seem to last just as long. It's something they are noted for that doesn't seem to matter either way.

 

Incidentally, the OP never said he had low oil pressure, just the rattling till it was warmed up.

You and I got off to discussing pressure or lack thereof. The rattling would imply low pressure, though.