[Capt Kirk]

I was always of the understanding that a bad rod bearing will quiet when under load and then start squawking once the engine is "slacked up". How's your oil pressure? I've had a couple modern 6 cylinder engines (Jeep 4.0) come to me with similar symptoms and in both cases it was piston slap. They both quieted down once warmed up...on cold start up they sounded like they we're going to blow up right then. One had a broken piston skirt and the other was just worn out. I've never experienced a stretched rod bolt and have always attributed that idea as if it were a unicorn sighting. In my (maybe flawed) thinking, the rod cap doesn't do a whole lot in the 4 strokes of an engine. On the intake stroke it's pulling the mass of the rod/piston down and whatever air/fuel resistance there is in the intake. Compression, power and exhaust are all working on the upper bearing. How can rod bolts stretch based on what he did??