I'm going to have the one of the advanced diesel classes check out my 6.2L. I'm going to have compression, glow plug, and injector tests done. Also try to isolate the knock in my head. Anything else I should have checked?

Have them check the muffler bearings and the power door lock fluid.

I would appriciate useful comments.

just a little humor there

don't put too much faith in injector pop tests for spray pattern. Pressure yes, pattern no, no dribbling. Have them check timing if they have a good meter.:rolleyes: :grd:

Are you getting white smoke/rough idle? That could be a stuck nozzle in an injector.

I've metioned this problem before. There's a knock in the right head and it blows white smoke out of the right tailpipe. Idle seems OK and it starts and runs fine.

Compression test is good a cylinder leak down test would be better.

I would put in a can of diesel injector cleaner in tank of fuel and drive several hundred miles to see it the problem clears up. Nothing wrong with having you engine checked out, especially if it is free.

Any kind of fuel pressure test I can do?

Can't test for pressure on vehicle. Knocking sounds like sticking injector. I'm with cougar john put it a heavy dose of injector cleaner. I have heard of good results on 6.2 injectors with marvel mystery oil added to the fuel.;)

Don't know your availability, but here for $8/injector, you can have them tested & cleaned.

Had it running in class one day and one of my inistructors was trying to diagnose the knock. The knock is high on the right side in what sounds like the 2nd cylinder from the rear. When he put his had over the drivers side of the intake and cut off the air the knock stopped completely. What does this mean?

My bad. A couple of instructors were looking at it today and when the passenger side of the intake is covered, the sound of blow back in the intake goes away but the cylinder knock is still there. The are 2 distict sounds that hit at the same time. 1 in cylinder (hard sound). 1 in the intake (more like a "thud"). It will go into the shop on Thursday for detailed diagnosis, but any ideas would be appriciated.

Noises on these engines are very hard to diagnose. Valves very rarely go bad except when influenced by outside sources(bolts geting dropped in intake, broken glow plug tips). I would start by methodical tear down, look at worn valve stems, bent valve, bad lifter, bent push rod, piece of glow plug imbedded in top of piston and last but not least, wrist pin knock caused by loose fit of wrist pin in rod.:grd:

They took the valve cover off and didn't find much. Maybe a bad seal on an exhaust valve. Probably have a burned intake valve. Knock sounds bad but the funny thing is all of the cylinders are firing (cracked all of the injectors). Could the sound be caused by the combustion of the diesel fuel?

6.2's have several places that noises can come from. A worn wrist pin bushing will cause a knock, a worn roller lifter will cause a tick, a chunk of glow plug imbedded in the top of a piston will cause a knock.

How many miles on this engine? Did they do a compression test? I have never seen a burnt valve on any 6.2 or 6.5. I have seen a few with bent valves usually caused by a foreign object falling into the intake manifold. Do the glow plugs look like they were replaced recently? I have seen quite a few cases where glow plugs blew a tip off and imbedded in the top of the piston. Sometimes they will rattle around in there and ding up the top of the piston and sometimes this can make the top of the piston come into contact with the bottom of the head. I would pull the head and inspect. Gaskets and new head bolts are not that expensive. Northern auto parts is a good source for felpro gaskets and bolts.

I would say over 100,000 miles. no comp. test. They checked the glow plugs. I think they were all good. They took the injectors out today. I was told they were popping at about 1500 lbs and that they are supposed to be at 2000. They're going to rebuild them for me.
Can OEM injectos be rebuilt to high-pop specs? What are high-pop specs? What is a set of high-pops worth?