Magnum 5.9 Timing Chain Noise?

New purchase, '01 2500 Magnum 5.9, about 250,000 KM. Has an engine noise, a "clack", more like a knock than a lifter tick. Previous owner had the truck for about 1 month, previous owner to him about the same. Both said the truck came with the noise and didn't get worse.
Doesn't use oil. Oil pressure is good according to the stock gauge.
Starts and runs fine. Idle is good with no noticeable miss, but doesn't have as much power as I would have thought it should have.
The noise appears after about the first 5 seconds or so after start up and gets worse as the engine warms up. It is particularly noticeable at idle.
A mechanic's stethoscope shows it loudest any place on the oil pan.
Second loudest would be either rocker cover.
It is almost impossible to determine if it is louder near the front or the back.
Not particularly noisy on the timing chain cover. Without the stethoscope it seems to be a bit louder toward the front of the engine.
Pulling one plug wire at a time does not change the noise, so I don't thing it is a rod bearing, wrist pin or collapsed piston.
The noise seems to be less at revs above idle, but hard to tell for sure.
An interesting observation is that if I crack the throttle, the noise disappears for an instant but goes "clackety clack" a few times just as the engine returns to idle.
I'm suspecting the timing chain, but would like to get some opinions before I commit to pulling everything off to get at the thing.

The Check Engine light is on. The previous owner told me the codes are:
P0138 - O2 Oxygen Sensor Circuit High Voltage (Bank 1 Sensor 2)
P0442 - Evaporative System Malfunction, Small Leak
P0445 - Chrysler: EVAP Large Leak Detected Conditions
I don't know what the symptoms of these codes would be or what the results would be, but I doubt they have anything to do with the noise.

Thanks.

I replaced my timing chain with about the same mileage on my own truck. It had slack, but nowhere near enough slack to slap the timing cover. Of course every vehicle is different. It's worth a check at least before digging into the bottom end. While your at it, may as well replace the thermo and water pump. May also want to be sure your plenum gasket didn't fail, since you mentioned lack of power. This would be a good time to replace it.

If it were a rod or crank bearing, you wouldn't make it 20 miles before spinning it. Wrist pins are rare problem makers on these engines, as long as you don't run the oil dry, but you'd have plenty of other problems then.

As for the codes, all of them are standard Gen 2 codes, I think just about every one of us has at least one of those. Nothing to worry about there. That O2 Sensor won't cause lack of power as it's the downstream one.

As for the timing 'chain' well, I wouldn't call the factory install a chain really, more a wannabe. It does seem to be chain noise, but you won't know for sure until you pull it.

The only real pain, is the radiator being in the way. If you don't mind pulling it, you can make the job real easy. You might as well replace the thermostat (only 190* if you want heat, its amazing how much colder 180* feels) since you will be removing the radiator. Flushing will never be easier. You can remove the AC condenser by just lifting it up out of the way and not disconnecting it.

Also, if you want to remove the alternator and compressor for any reason. Don't remove them individually, remove the bolts from the bracket they attach to, it less bolts and reassembly is much easier (the compressor mounting bolts like to seize and snap in my case)

dudeman2009,
That's encouraging news. I've been studying the service manual to see what all is involved in changing the chain set. Definitely the rad should come out but at least the AC condenser can stay, or so says the manual. I have to work outside on the thing and I will have to wait for decent weather before I tackle it. It's been pretty damp around here lately.

timing chain will be heard at idle at all times in my experience. you might actually have lifter tick instead.

Well, the symptoms seemed to point to a very worn timing chain, and the weather was decent, for a change, so I decided to just get at it and have a look at the chain. Fortunately for me there is very little rust on the truck and I was able to get the timing cover and all the stuff to get at it off with no bad scenes.
When I had a look at the chain it was obviously worn, but there is no evidence of the chain hitting the timing cover.
With one side tight, the other side has about ¾” of deflection at the centre of the span. “This has to be my problem” Sez I to me.
Well, not so fast. I did a chain stretch measurement as outlined in the service manual. The manual allows up to 1/8” stretch before replacement. I measure about 1/16”, possibly as much as 3/32”, but certainly not 1/8”.
I wonder what the deflection would be with 1/8” stretch?
This troubles me, but I’ve ordered a gasket set and timing chain and sprocket set. I expect it will take about a week before I get them, and then I’ll have to wait for weather to install.
Has anybody else experienced this?
I’ll report back when things are up and running again.

Well, it looks like I called that one wrong.
I installed a new timing set and appropriate gaskets. Drained the oil, re-filled with 10W30 and changed the filter. Checked oil and filter element for traces of metal. None found.
Fired the engine up and the knock is still there, but not quite as loud. There is no noise at all for the first second or two after start up. Then the knock can be heard. It gets worse as the engine warms up, but still not as bad as it was before the timing set and oil change. It is worst at idle and almost disappears above ~1500 RPM or so.
Perhaps this is because of the new oil?
I warmed the engine up to operating temperature and tried to determine the location of the knock. It might be a bit louder on the right side, but it’s very hard to tell. I decided to do a compression test with the logic that if I had an intake valve with excessive clearance it might show up as lower compression. I don’t think an exhaust valve with excessive clearance would affect compression.
I tried to get the connection for the starter solenoid off the starter to connect a remote starter button, but no success. I referred to the shop manual and it just said to disconnect the coil to do a compression test. I couldn’t get the primary connection off so I just shorted the secondary to ground.
I thought that just disconnecting the coil was rather strange as the fuel injectors would still be firing and possibly washing down the cylinders a bit and affecting the readings, but I went ahead with the test anyway. These are the results in order of how they were taken:

1 = 170 PSI
3 = 137 PSI
5 = 137 PSI
7 = 125 PSI
2 = 170 PSI
4 = 170 PSI
6 = 162 PSI
8 = 100 PSI

As you can see, this is not very good, but the engine starts well and runs quite smoothly.
Now, I found an interesting thing with the plugs. They were well worn and looked like they had a lot of time on them, but all were quite uniform in a light grey colour, except for # 8. The tip was OK, but the insulator and body were quite black and crusty, as in oil fouling, yet the engine does not miss and the previous owner said it doesn’t burn oil.
I don’t know if this might be pointing to my noisy cylinder or not.
The next step is to pull the rocker covers and rotate each cylinder through it’s cycle to see if I have any valves with excessive clearance, but that will have to wait until the weather smartens up again.

If you have a leak down tester that would be grand.

I have a leak down tester and may use it to see where my compression is going eventually, but for the moment I'd like to figure out the cause of my noise.

Sticky/stuck lifters maybe? Exhaust manifold gaskets. Both make a crappy noise when not working correctly.

have tried using some heater hose like a stethoscope?

Definitely not a manifold gasket. Very possibly a lifter problem, but only one.
I'll try the heater hose thing, good suggestion.

Possibly a rocker arm as well

Tried the heater hose but still nothing conclusive. The noise just seems to be coming from everywhere, can't pin it down at all. I'm pretty sure the frequency is every other crank revolution, too slow to be crank revolution. The exhaust note indicates perhaps a weak cylinder, but not very bad. Definately not an exhaust leak. Worse at idle, diminishes with rise in RPM. I'd suspect a rod bearing except there is no metal and it's been going on for some time (reportedly). Good oil pressure. I would expect that a rocker or bent push rod would be easy to localize the noise. It's a head scratcher alright.

have you tried running the engine with the valve covers off? Maybe you'll be able to see something, or feel something, that doesn't seem right. Is it an automatic? Maybe the flex plate is cracked or loose? Maybe tc is breaking?

I’ve been giving this noise thing a lot of thought, and here are the latest ones.
I had the truck in for steering issues, and while on the pit the mechanics and I did some more analyzing. A stethoscope doesn’t seem to help much because the noise just seems to telegraph everywhere. Rocker covers or oil pan, not much difference. But while on the pit a length of 3/8” fuel hose seemed to localize it towards the back of the pan, no particular side, which might indicate a rod bearing, or a broken flex plate.
I did some experimenting, thinking of the flex plate thing. When first fired up, there is no noise for about a second or so, The noise then appears, is worst at idle, and gets worse as the engine warms up. Again, no difference in noise when any particular plug wire is pulled. Oil pressure is good. An increase in no load RPM decreases the noise. If I put it in gear with my foot on the brake the noise diminishes greatly with increased load, but the revs have risen as well. The noise is not always constant at the same RPM. Sometimes, especially at idle, it is quite loud. Sometimes, just audible.
I put a timing light on it to see for sure if it is at crank or cam frequency. Definitely crank frequency as the noise is at twice the timing light frequency. This would indicate to me that it is not a valve train related noise.
I suppose the next step is to pull the starter and the inspection plate in front of the flywheel housing and see if I can find anything suspicious in there. Perhaps un bolt the torque converter and slide it back as far as I can and see if a mirror will reveal anything on the flex plate itself.

Well, it wasn’t raining today, for a change, so I decided to investigate the possibility of my knocking noise being a cracked flex plate.

One nice thing about the 2500 4x4 is that there is enough room to work under the truck that for a lot of things, so jacking and blocking is not usually necessary.

So, off came the two braces from the block to the bottom of the transmission torque converter housing. Off came the starter, and off came the inspection plate in front of the housing.

First glance revealed nothing suspicious. No marks anywhere, no metal bits, no rusty areas that might reveal a crack.

I pried the engine over in the direction of rotation about a 6th of a turn at a time. All torque converter bolts were tight. No sign of cracks anywhere. I tried to pry the flex plate toward the front of the engine. No perceptible movement. I tried prying it backward. You could see a bit of relative movement between the flex plate and the torque converter as the flex plate did what I suppose it is supposed to do. Flex a bit. If I let it spring back quickly I could here a slight “clunk” like the torque converter was coming up solid on the crank, or crank bolts. There was no sign of rust or filings to indicate it was the hitting the bolts, so I assume the pilot protrusion is coming up against the crank.

I thought I might as well put the starter back on, less the inspection plate, fire it up and have another listen. So I did. I brought out my trusty length of 3/8” fuel hose, plugged my bad ear and used my good ear to see if I could pin point the noise.

Definitely not coming from the flex plate area. It was loudest close to where the oil pan meets the block, and loudest towards the back of the engine. No noticeable difference between left and right side.

Off comes the starter and back on goes the inspection plate starter and braces.

So, unless there is a serious crack in the plate around the hub, which I see no signs of, I am reasonably sure that the flex plate is not my problem, but what the hell is?

It’s kind of looking like a rod bearing, in spite of the good oil pressure, or perhaps a cracked or collapsed piston, or wrist pin, most likely on # 7 or # 8.

I had a look at the possibilities of dropping the pan in situ. It’s a bit tight to the front cross member, but there should be enough room to angle it down from the back and clear the front axle.

It wasn’t raining yet, and god hates a coward, so I drained the oil, un-bolted the pan and tried to wiggle it out. No go. It was hitting on the inspection plate. So, off come the braces, starter and inspection plate. Again. Now the pan comes off quite easily. Nothing ugly in the pan. None of the rod big ends wiggle in directions where they shouldn’t wiggle.

I pulled the caps off 7 and 8. So far so good. Bearing wear looks normal. Crank looks like new, but I’m running out of daylight. Time to quit, put the pan back out to keep the nasties out and try again some other day.

I’ll have to do each rod big end, check both shells, and mike the crank journals.

I’ll post an update when I get that done.

It didn’t rain today! I exercised my right, as being self employed and played hooky to do some more investigating as to my engine noise.

I checked every con rod bearing and crank journal. My factory service manual tells me that the journal diameter should be between 2.124” and 2.125”. I’m not a machinist and it took me most of the day, checking and re-checking, but as I measure, they were all ~ 2.125” +_ 0.0005”. All crank journals looked like new.

All con rod bearing shells looked very similar. None of the lowers showed any copper or score marks. All of the uppers showed copper, some worse than others, but not much. No scoring or other bad things. All clearances measured between 0.004” and 0.005”. The manual states that clearances should be between 0.0005” and 0.0022”.

Because I am only hearing one particular knock, I fully expected to find one rod bearing with seriously excessive clearance. Didn’t happen. Obviously, I have some bearing wear, but they are all pretty much the same, which doesn’t explain a singular knock.

However, I did see something that could probably explain that knock.

I am going to install a new set of con rod bearings. The cost is relatively small, and seeing as I am into it this far anyway, it will be worth it to me if it helps to prove the point.

To be continued.

until I finished reading your last post, I was going to say, if you're seeing copper you might as well replace them while you're there. But before you do, try prying carefully, back and forth, to see how much end play you have on the crank.
just for peace of mind, I'd run plasti-Guage on every journal with the new brgs, one by one, just to be absolutely sure you don't have an outlier big end, or bad brg. Make sure it is fresh Plasti-Guage, cause if it's old you won't get an accurate reading.

I checked for crank end play when I was checking the flex plate. I didn't put a dial indicator on it because I couldn't see or feel any perceptible movement. There is probably some end play, but not excessive.