About 7 years ago, I inherited a 2000 Dodge Ram 2500 5.9L Magnum from my grandpa. He took meticulous care of his vehicles, but poor health had this thing sitting idle in the Phoenix, AZ heat for at least 2-3 years.

It had just under 100k miles on it when I got it in 2014. Mostly been a secondary vehicle for me, but I’m trying to get it back in shape for a daily driver.

In all her glory


Ram tough, erwahdever

When I got it, it had an alternate LPG system, which I removed. I could have been more meticulous with my electrical wire work in this removal, but there’s no DCTs being thrown, so that’s a win.

Had the OEM fuel pump go bad on me. Replaced it with OEM part, that went bad less than 6 moths later. Frankenstiened the two together to make one “working” one. That hodgepodge piece has been “good” for the last 5 years and 15k…

Did the block test through the radiator and the liquid stayed blue (there was the slightest greenish tint at the top of the bubbles, though). Did it 5 times to really verify that it would be worth investing anytime and money into. This photo is from about 3 minutes in, all warmed up with fan going and coolant circulating.

Block test

No rust on frame.

Dry compression test:
1- 155
2- 155
3- 150
4- 150
5- 150
6- 145
7- 145
8- 145

Right now, there are a couple issues I’m chasing.

#1. Lack of power, rough idle, weird shifting.

I dropped the transmission pan and changed the fluid and filter. Fluid was low. Definitely a Hostess Donette of shavings collected on the magnet, but no chunks. Helped shifting a bit. Less noise in reverse and neutral. But timing of shifts is still off.

Hostess Donette of shavings

Changed spark plugs.

SP 1,3,5,7


SP 2,4,6,8

I cleaned the throttle body and replaced the IAC, MAP, and TPS, and a CRACKED HOSE from PCV to manifold all at once, so not 100% sure which helped, but it smoothed out the idle a bit. At least until it got warm… Then, while in Drive and stopped at a light, it would start dropping and surging from 650 to 600 RPM and back up, over and over. And, when in Park, it would surge from 650 to 700 RPM and back down, over and over.

cracked hose from PCV to manifold

During the throttle body cleaning, I checked the plenum. A magnet stuck, so it’s definitely the original plenum. Looking inside, I see no liquid or pools of oil, but I did see what looked like dark cake/mud. I don’t loose much oil, if any.

Inside manifold looking down at plenum, left side


Inside manifold looking down at plenum, right side

Changed the PCV valve and disconnected both 1/1 & 1/2 upstream O2 sensors, and the truck idles perfectly and seems to shift better. I could smell a noticeable sulphur smell with them unplugged, but not before.

I did look inside one valve cover and saw what looked like the color of a coolant oil mix…

inside left valve cover


wider shot of left valve cover

Still feels like some power loss. I never knew the truck new, but for such a big engine, just seems like there should be more punch when stepping on the gas… Just feels sluggish to me.

Thinking clogged cats, at this point. What do you all think?

Also, I realize that the plenum and gasket likely need to be replaced, which could be what fouled the O2 sensor and clogged the cats. I have 4 new upstream/downstream O2 sensors, but hesitant to put them in until I find out what might have hurt the previous ones (unless they just succumbed to old age… OEM and 126k miles…never got a CEL or DCT for any O2 sensor)

Thoughts on issue #1?

And…

#2. Coolant loss, smell on start up, light light light white smoke, exhaust sounds almost underwater or muffled. It’s more of a loud gurgle than a roar.

I feel like the muffled exhaust sound might have more to do with issue #1 and clogged cats.

Never have I ever seen or smelled or felt evidence of coolant in the oil.

Block combustion test passed multiple times.

Seems like the longer it sits, the more smoke there is. But that could also be influenced by the cool, moist fall/winter/spring here in the PNW, as that is when it sits the longest.

Valve cover gaskets?
Plenum?
Head gasket?
Cracked head/block? (Please, no!)

In a perfect world I’d:

1. Replace head gaskets
2. Address any other top end issues, valves rings, seals, pistons, etc…
3. Aluminium plenum
4. Valve cover gaskets
5. New cats

But, unfortunately, I’m not made of money… So, what do you recommend that I tackle next?

Thanks for any input!

 

Plenum looks to be OK. The stuff you see in there is likely from the PCV system. Also, get your PCV valve from the dealer, they are actually the correct flow rate. Same can't always be said for the aftermarket fellers.

Change your O2 sensor. NTK or Denso sensors only please. The other brands just don't work as well on these trucks.

What plugs did you install? Did you reset the PCM after changing a bunch of sensors? Did you use mopar sensors??

 

Hey heyyou! I feel like I know you from reading all your posts lol

I did get a mopar pcv valve.

Changed all four O2 sensors tonight and replaced them with NTK sensors.

The plugs are Champion copper with .40 gap

Unfortunately, I got the sensors from an auto parts store. TPS and IAC are MasterPro and MAP is either Duralast or Delphi, can’t remember.

As for PCM reset, I left the battery disconnected for 30 mins or so. That’s the only way I know how to reset it. Is there another way?

With the new O2 sensors, I feel more pull and the shifting feels better…beforehand, it was shifting before 2000rpm…now it’s closer to 2500rpm. Slight hard start is completely gone.

It’s interesting because when I unplugged the upstream O2 sensors it was perfectly smooth idle. But with the new ones, there’s a slight surge again. It’s very slight. Like 650-675.

Overall, I’m pretty happy with how it’s running now!

My biggest concern at the moment is where the coolant is going…any ideas or thoughts on where it could be going?

Thanks for all the help here and your contributions through this forum!!!

 

PCM reset is good.

As for coolant leaks.... Best bet is to clean the engine off good, drive it for a bit, then start poking around with a UV flashlight. Rumor has it, coolant doesn't need dye added to it, to glow nicely under UV light. Unfortunately, there are a LOT of places coolant can escape, but never hit the ground. The bypass hose between the water pump, and intake is one spot. It's under the a/c compressor, so you simply cannot see it. Freeze plugs like to rust out, and weep as well. And of course, there is always the water pump itself. You don't seem to be burning it, and that's always a plus.

 

As I was falling asleep last night I started to wonder if the mini cats and cat are clogged so much that I’m not seeing coolant burn off… like maybe the gasket or head is really cracked but it’s appearing less of an issue because the cats are all so clogged that it’s not even coming out…

But the hydrocarbon combustion test…seemed to suggest it’s not cracked.

I definitely see faint white smoke on start up. And there’s some water drip out of the exhaust tip on start up, for sure. But it’s not billowing out while driving…

And, the truck almost feels like it’s got the parking break on. It’s not, but the best way to describe what I feel is a power loss is that the truck is fighting some resistance. Could that be overwhelming back pressure?

Might try to loosen the bolts at the manifold and see if it feels any better. That should tell me if the Cali mini cats are clogged…

 

Pull the front O2 sensors, go for a drive, it'll be louder, but, see if it runs any better.

 

The lack of power is probably due to the death flash. Have any stickers under the hood or on the PCM saying "Authorized Dealer Update/Flash?"

My 96 I lost coolant and oil with no smoke, turned out to be cracked heads. I would do a leakdown test.

 

When I disconnected the O2 sensors' electrical connectors, it ran super smooth, no surge. When I put the new NTK ones in it ran better, but the slight surge is still there. I'll pull the upstream sensors and see how the vacuum test goes when opened up before the cats. That should tell me for sure about any restrictions from the cat back.

I attached a video of the vacuum test. It's connected at the brake booster nozzle. O2 sensors are in. It's warmed up. Notice the very slight surge at idle, steady at load, and then it falls into a more pronounced surge after being at load. The vacuum loss when the accelerator is pressed is consistent with the lack of power/throttle response that I feel. It all seems to suggest to me that there is some air flow blockage somewhere because it can't clear the air as quickly as it's taking it in.

Not that I see. It had a second LPG fuel system, so there was a lot of work done in there by non-dodge folks. Could have been removed, I suppose.

Damn, that really sucks to hear. Did your hydrocarbon combustion test come up negative too? I heard those are supposedly very accurate.

Here's my oil change today. I did run half a can of seafoam through the last 150-200 miles.


And I'm pretty sure I found the coolant leak.

Saw this while removing oil filter...


Followed it back to the front freeze plug on the block...


Ta-dah!

Checked the other freeze plugs on the side of the block and they show no corrosion.

I also attached a video of my exhaust on start up this morning. It was chilly and grey out, today too. Fall is here.......

Just trying to figure out next steps. I feel like I need new cats, at least––maybe a new exhaust set up from the cats back. Right now the leak down test seems reasonable. I guess there's no point in replacing the exhaust if I can't figure out what caused it to get clogged. Hoping there's no cracked heads.

FWIW, I had a blown heater core and fixed that years ago. A couple years later, the radiator went on the freeway. Smelled the coolant and saw it on my windshield, the temp gauge started rising quick. I pulled off immediately and put in a new radiator on the side of the road. Never overheated to the point where there was tons of steam or anything.

Thanks for the interest and feedback!

 

I wrote an in-depth follow up post with pics and a couple videos. It never posted. Thinking that it got flagged or something for the video attachments

 

Correct. I approved it.

If one of your freeze plugs is in that condition, the rest aren't too far behind.... That said, I replaced one on my truck, behind the drivers side motor mount, the rest were still fine when I sold the truck a couple years later.

Test with the O2 sensors out before you condemn the cats. Them fellers ain't cheap.