Six weeks ago I bought an 01 2500 5.9 gas regular cab. It only has 25k on it so I thought it was a good deal. After a few days I realized that the truck was suffering from the typical blown plenum gasket (a lot of pinging and the intake made a whistling noise when cold). I replaced the plenum gasket (felpro intake set) and fired the engine up, it ran good for about a minute then shut off. It was hard to get it to start again. I can get it to run now but it sounds like a bolt is bouncing around under the plenum while the engine runs. I thought that one of the bolts holding the plate to the bottom of the intake fell off and was bouncing around on the lifters but when I took the intake back off there is nothing out of the ordinary, I am 99.99 percent sure that I did not drop anything into the engine. Any ideas?

 

It could be a lot of things. I wouldn't drive it until you figure out what is going on. My thoughts are you either aren't getting oil where you need it or you've got some detonnation.
The first thing I'd do is check the oil to see if it's got water in it (will look muddy). I'm not sure how advanced you skills are so I'm sorry if it sounds like I'm talking down to you but easy things first, Occam's razor and all that...
Make sure the distributor cap and rotor are on right and verfiy the plug firing order. Make sure the fuel injectors are seated properly (both ends and electronic harness).
Make sure the sensors and vacuum lines and are connected properly. Make sure the PCV valve and breather are connected correctly. Make sure a vacuum line didn't break during the process and you didn't notice.
Reset the PCM (disconnect negative battery terminal and turn on engine switch for about 20 seconds).
When it's running, check to make sure there's no fuel leaking anywhere.
It might be a leak at the manifold. With it running, spray some carb cleaner around the manifold and see if the rpms pick up. Some people blow a puff of cigar smoke and look to see if it gets sucked in anywhere but that sounds a little too dangerous.
Next pull the plugs and see how they look (oily, burt, cracked, ect) and do a compression test if you have a gage. That will tell you if you have a valve stuck or something more serious. Squirt some Marvel Mystery Oil in each cylinder when you put the plugs back in.
Next I'd pull the intake again and make sure the intake gaskets are lined up correctly. Check all the oil ports to make sure nothing is clogging them.
I'm guessing when you had the intake off you shook it around to make sure nothing was rattling around, if not, give that a shot. Squirt some more of the Marvel Mystery Oil on the rods and lifters then bolt the intake back on.
If you still aren't getting anywhere, I'd pull the valve covers and see if anything looks askew.
I'd recommend doing the Seafoam in the oil and intake but I'm concerned that could cause some harm if things aren't properly lubricated.
Anybody else have any feedback? Good luck.

 

have you got the intake off now ?
count all the bolts in the bottom of the belly plate. are they all there ?
touch/wiggle everything in the lifter valley. anything loose or rattling ?
remove spark plugs and turn engine with a ratchet ? do it tick or knock at any point ?
turn the intake upside down and shake it around. anything inside?

with everything tied back out of the way, can you spin the starter and check for noise ?

 

Currently the intake is off. The engine ran good without noise before I started the gasket replacement. The noise does not sound like detonation. It sort of sound like a small bolt being rattled around inside a tin coffee can.
None of the lifters or pushrods are loose. Some antifreeze did get spilled in the valley while removing the intake is it possible for a lifter to get contaminated with coolant insted of oil? What would the antifreeze do if it gets mixed into the oil?
Nothing is loose inside of the intake. I think I will try and turn the crank with a wrench and listen for noise. Also, when I replaced the intake I did not use the end gaskets just RTV silicone. Is it possible that the intake sits lower without the end gaskets that it slightly contacts one of the lifters?

 

Did you change the oil immediately after you completed the plenum repair? If not, you should have, regardless of whether you know it was contaminated or not.

 

RTV instead of rubber gasket won't hurt anything. there's no chance of contact to lifters or pushrods.

coolant in the oil is not good, but a little bit wouldn't be the end of the world. it would be like a leaking head gasket and the oil would be milky. if some gasket material was to stop up the screen, you'd notice a loss of oil pressure.

if you don't find anything by spinning the motor, remove the valve covers and turn the motor.

 

did you only replace the gasket? if so it probably blew out again. You CANNOT just replace the plenum gasket, it will not fix the problem, but temporarly hide it. You need a Hughes or APS plenum kit. If not dont bother replacing it.

 

It sounds like the problem is coolant in the oil. Not uncommon when pulling the intake if you didn't drain the coolant properly first. This isn't a big deal unless you don't do anything about it.
Pull the oil filter and drain the bad oil out. I think dhvaughan recommended this to me--with the oil plug out, pour some diesel fuel in the lifter valley and let it drain out the bottom. This helps to get rid of contaminants. I would still squirt some Marvel Mystrey Oil or at least some SAE 30 on the rods, lifters, the valves, and the cylinders before starting the engine. The idea here is to get some lubricant where it wasn't before.
Also add about 1/3 can of seafoam to the fresh oil. Run the engine for 100 miles (assuming no rattleing) and change the oil and filter again. If it looks good and clean refill with good fresh oil and filter and change it in 3000 miles. If it's muddy looking again, you've good coolant leaking into the oil somewhere.

 

UPDATE:
I took all of the pugs out so that i could turn the engine over and listen for any funky sounds. Well, the number 8 spark plug has almost no gap! They are Bosh platnums (single tip) with only a few hundered miles on them. The squished one also looked oily, probably from the blown plenum. I assume the piston hit the plug?

 

i wouldn't think the piston could hit the plug. it just doesn't rotate up that high. it might have been dropped somewhere along the way.

any funky sounds or feel.