Lifter tapping
I just bought an 02 F-250 Crewcab w/ 7.3. I am quite impressed with the truck. It is nothing short of luxury for me.
There is a loud tapping from the engine. Mostly heard at idle and increases in speed with engine speed. The tapping is not as noticeable at highway speed and can't hear it at all if I turn the radio up enough...
. I am pretty sure it is a lifter. I am going to try changing oil and adding (1) quart of Marvel Mystery Oil and adding a pint of Sea Foam to a full tank of fuel.
I normally don't go for the "mechanic in a bottle" fixes, but a stuck lifter can free up with solvent.
Any comments on the above products. If there is something better, I will use it, and I don't want to trash a fine engine.
Thanks, Earl

I would avoid any oil additives with the PSD. They are designed to use engine oil at very high pressures to drive the fuel injectors.
Try this before you say it's a lifter. Rev the engine up to 2500 rpm and cut the ignition key and try and hear the lifter tapping as the engine winds down. My guess is that you will not hear it. Most cases it's an injector knocking and when you cut the ignition that tapping will go away even if the engine is still turning over. You could also try coasting down a hill with the key off as well. If it really is a lifter, the sound will not change whether the key is on or off. If it comes and goes with the ignition power then for sure it's an injector.
So you still think it's a lifter?
Remove the valve cover on the offending side (both if you want to be sure) and check the bolts that hold the rocker arm pedastals down. I've never dealt with that part of the powerstroke engine so I can't give you any pointers other than I've read about some of the pedastals coming loose under the valve covers.
I still think it's an injector, though.







