My 7.3 in my 92 f350 has had a pretty distinctive knock in it for at least 110000 of its 190000 miles and who knows how long before we got the truck. Never really bothered anything that i know of. Truck feels plenty strong and it dont seem to be getting any worse. When i changed the oil in it today i noticed a big difference in the knock. It got right much quieter than before the oil change but was still there. My mechanic tried to tell me it was a rod knock but i just dont buy that. Anyone have any suggestions on what could be causing it?

 

Does the knock diminish after the engine is warm...... mine does and I think mine is piston slap. When I had that piston out I found the sides had some scrappings.

An audible knock could also be a bad injector firing early..........

 

no it stays steady no matter cold or hot

 

hmm, mine does that too, but only for a short while, it might be a bad injector like PLC7.3 said, i shure hope for you its not a piston slap or a rod knock...