Hello all, i've got a 1994 Dodge Ram, 2500 with the 318 "Magnum 5.2", multi port injected, 149,000 miles.
i bought it back in Febuary, and from then until now, its had this rattling/ticking and sometimes knocking sound coming from the passenger side of the engine, coming from under the valve cover. it sounds like a knock on a cold start, and turns into a faint tick after it gets to normal temp (hot). and when under acceleration, makes a loud rattling noise like the rocker arms are falling off. since then, i've performed 13 oil changes in the 17,500 miles i've put on it. i have used Sea Foam, Lucas, Rislone, cheap oil, expensive oil and even different brands and sizes oil filters trying to get rid of this noise that has been driving me insane. i put on a new timing chain, new plugs, new wires, new cap/rotor, and must have run 10 gallons of fuel injector cleaner thru it so far. it doesn't have exaust leaks, i've taken off the engine belt and let it idle without it, so its not a pulley making this noise, and i did check the tourqe on the rockers, and their tight. i also replaced the leaking plenum gasket that was a common problem on the Magnums.

i've also heard that these engines even did this when they were new, is that true?

what do you think could be making this noise?

 

could just be your pcv valve

 

it has a new PCV valve, crank breather, and the hoses too. anything on the engine that was easily accessible, i replaced. that includes every sensor, all the vaccum lines, even the EGR valve.

 

Did the guy give you any history on the truck when you bought it?

Does it have good oil pressure? Could be a lifter going out.

 

its got great oil pressure, about 50psi at idle, 80psi on the highway.

and yeah, i've heard the history on it, its got quite an abusive, negected history.
a family member bought it new, so i've heard the whole story from his kids.
after it was new, it went six years and 71,000 miles on the factory oil.
in 2000, the original battery died, and he took it to Walmart and had a new one put in. one of the guys there checked the oil, nothing on the dipstick. they reccomended an oil change, he had them do it, and that was its first oil change. a few years, and about 50,000 more miles later, still running on the Walmart oil, he bought a 37ft travel trailer and hitched it up. got five miles and it overheated so hot that the radiator busted. a new rad, new coolant, and round two, overheated. stopped for 30 minutes, let it cool down, round three. made it about ten miles this time, overheated again, busted the new rad. he had another new rad put in, and then parked it until i offered to buy it in Febuary of this year. i took it home, and did the second oil change of its life, and done 12 more oil changes since then. now when i drain the oil at a 3,000 mile change, its still brown like out of the bottle, so i think the motor is clean now, hopefully.

 

Geez i knew these engines could take a beating but DAMN...

After reading all that here's my take on the problem...probably a craked head from overheating, badly worn lifters. Are you sure the sound is from the top end and not the bottom.

 

Wow, I hate is when people do no maintainence on their vehicle..

Is the sound on both sides? You most likey have loose rocker arms. They need to be retightened to spec. I need an adjustment too, remember that it's a pretty messy if you're going to do it yourself.

 

in response to "97blackram", not saying your wrong, but i don't think it has a cracked head for three reasons. the first is i ran a compression test after i got it and all eight cylinders had over 140 psi, i did this when i performed it's first tune up (plugs, wires, cap/rotor, air filter, etc). the second being that, even after all that overheating, it amazingly burns no oil. valve seals and rings are still holding up. and the third is it holds its coolant level, and doesn't leak anything out the head gaskets either.
it could have bad lifters, especially with them being hydraulic, being run low on oil could have caused them to wear prematurely.

EDIT: in response to "97blackram", i forgot, yes the noise is coming from the top, not the bottom of the engine. it sounds like its behind the passenger side valve cover.

and in response to "Ram me", it seems like the noise comes only from the passenger side, and i did retourqe all 16 rockers, to 21ft pounds as the Chrysler service manual says. only a couple were loose, but it didn't fix the problem.

 

Hold the vaccum line from the PCV Valve to the intake manifold. You should feel small vibrations the same time you hear the noise. My PCV Valve/lines made noise once, sounded like loud taps that were very inconsistent. I could feel it through the vaccum line. Went away the next day.

 

my new pcv valve that i'm about to replace tomorrow makes a loud intermittent rattling at idle. it rattles when it opens up and makes a whistling noise when its closed. if i grab the hose when its closed (whistling) and wiggle it then it'll rattle for a second (open) then close again.

the valve opens when you raise the rpms and increse the vacuum on the intake manifold and increse the crank case pressure. at idle, the vacuum and crank case pressure is low so the pcv closes. to test it all you have to do is pull it and feel for vacuum at idle.

for the rocker arms, you have to rotate the crank by hand when you torque them. i believe they need to be level with the head when you apply the torque, one of the guys that has HS roller rockers could tell you exactly how to torque them.

on a side note, my dad said that the way he did it on his 75 v8 camaro was to get all of the rocker arms loose and run the engine, then tighten them until they got quiet. it was a lot easier back in the 70's.