Black sluggish consistency in coolant

[Gladiator.916]

Hello gladiator fam,

Question for yall noticed black residue in the coolant reservoir. Read on forums and first thing first pulled and checked the oil cooler, got the cooler pressure test came back good. Next pulled the high pressure egr, pressure tested came back good. Low pressure egr looks good too. Next though is head gasket, at this point wondering if anyone else had the same situation, before I start pulling the head. I’m at 58ish k miles. See attached picture of the black sluggish consistency that came out of cooling system.

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[GoatPowder]

Best hillbilly test you can do, pop the rad cap (cold) and stomp it for a few seconds. If it's 'ol faithful: either combustion gas from head gasket is getting in or EGR cooler failed.

Is the residue carbon-y or milky when it's not in the cap?

If it greys out it's oil, if it's deposits your looking at carbon AKA EGR

Did you test the EGR and oil cooler at coolant pressure or oil pressure?

 

[Gladiator.916]

Best hillbilly test you can do, pop the rad cap (cold) and stomp it for a few seconds. If it's 'ol faithful: either combustion gas from head gasket is getting in or EGR cooler failed.

Is the residue carbon-y or milky when it's not in the cap?

If it greys out it's oil, if it's deposits your looking at carbon AKA EGR

Did you test the EGR and oil cooler at coolant pressure or oil pressure?

I wish I can do the hillbilly test . It’s taken apart already.

 

[Gladiator.916]

Best hillbilly test you can do, pop the rad cap (cold) and stomp it for a few seconds. If it's 'ol faithful: either combustion gas from head gasket is getting in or EGR cooler failed.

Is the residue carbon-y or milky when it's not in the cap?

If it greys out it's oil, if it's deposits your looking at carbon AKA EGR

Did you test the EGR and oil cooler at coolant pressure or oil pressure?

They tested at 23 psi from the coolant side. I’ll rig up plate tomorrow to block off oil side and pressurize oil side.

 

[GoatPowder]

I agree, back pressure would be more than that at anything other than idle. Didn't want to jump the gun but photo looks like carbon; my money would be in failed HP cooler. It's most likely to cavitate and crack (isb's had this issue for years) but kind of hard to determine unless the motor bolted back up.

Honestly if the cap wasn't venting it's unlikely a HG. Considering you have coolers, I'm assuming the DOC is intact. So you should've had regen issues before noticing any build up; if HG was failing you'd burn a bit of coolant at every start up and the DOC hates that

 

[Hollandbriscoe]

The oil cooler is leaking into the coolant, the same thing happened to me. They had to replace the oil filter housing assembly. Took a month to get parts.

 

[Gladiator.916]

The oil cooler is leaking into the coolant, the same thing happened to me. They had to replace the oil filter housing assembly. Took a month to get parts.

Yea weird thing is that oil cooler pressure test came on good.

 

[Cadguy]

I just finished restoring my 2021 from an oil cooler failure. That's exactly what you are looking at.
Had to change EVERY hose, as they were soft from the oil, but it had been in there for a while.
The seller thought it was a blown engine, but just the oil cooler.

 

[Gladiator.916]

I just finished restoring my 2021 from an oil cooler failure. That's exactly what you are looking at.
Had to change EVERY hose, as they were soft from the oil, but it had been in there for a while.
The seller thought it was a blown engine, but just the oil cooler.

Did you pressure test the oil cooler to see if I had a leak?

 

[Cadguy]

No, just installed a new one, but for the coolant flush, I bypassed it temporarily until I was finished with the flush. Runs perfectly well, now that it’s all done.

 

[Gladiator.916]

No, just installed a new one, but for the coolant flush, I bypassed it temporarily until I was finished with the flush. Runs perfectly well, now that it’s all done.

Got it. I’ll test my high pressure egr if that shows good will order the oil cooler assembly and wish for the best

 

[rharr]

No, just installed a new one, but for the coolant flush, I bypassed it temporarily until I was finished with the flush. Runs perfectly well, now that it’s all done.

Went you guys say Oil cooler, are you talking about the heat exchanger down by the oil pan drivers side of the engine?

Are you saying that whole assembly heat exchanger and oil filter housing has o-rings in it to seal against the block and those fail?

 

[Cadguy]

The o-rings don't fail, the cooler itself fails, I imagine the plates separate. It's a common design, we use a large style of this type of cooler for industrial uses...
it is an extremely efficient design, as it offers a lot of surface area because of the multiple plates.
It is a stack of plates, alternating coolant and oil, but in my case for industrial us, every other plate flows the cooling medium, and every other plate carries the "cooled" medium.
In this case the cooling medium is the oil, and the "cooled" medium is the oil.
When they split, it is usually a very small fracture, and the oil pressure has enough differential that it pumps it (oil) into the coolant, which is at a much lower pressure, which is, ironically, a good thing in this case, as you wouldn't want coolant pumped into the oil... very bad
Unfortunately in our case also, you have to replace the entire oil filter adapter with the cooler mounted to it. Can't buy the cooler separately.

 

[rharr]

The o-rings don't fail, the cooler itself fails, I imagine the plates separate. It's a common design, we use a large style of this type of cooler for industrial uses...
it is an extremely efficient design, as it offers a lot of surface area because of the multiple plates.
It is a stack of plates, alternating coolant and oil, but in my case for industrial us, every other plate flows the cooling medium, and every other plate carries the "cooled" medium.
In this case the cooling medium is the oil, and the "cooled" medium is the oil.
When they split, it is usually a very small fracture, and the oil pressure has enough differential that it pumps it (oil) into the coolant, which is at a much lower pressure, which is, ironically, a good thing in this case, as you wouldn't want coolant pumped into the oil... very bad
Unfortunately in our case also, you have to replace the entire oil filter adapter with the cooler mounted to it. Can't buy the cooler separately.

THanks for the update. I have dreams of someday finding a bigger heat exchanger to replace the OEM one.... It's hard to believe the mounting dimensions of ours is so unique that it can't be cross referenced to something similar.

Found this btw

https://dandjdiesel.com/eco/

 

[Rusty PW]

THanks for the update. I have dreams of someday finding a bigger heat exchanger to replace the OEM one.... It's hard to believe the mounting dimensions of ours is so unique that it can't be cross referenced to something similar.

Found this btw

https://dandjdiesel.com/eco/

Think that oil cooler kit is for a Gen 2, not a gen 3. Don't know what the difference is.

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