dirty Coolant isx cm2250

[cjcool]

We have an ISX cm2250, it all of a sudden has dirty coolant, we did a coolant flush and it was dirty again within a day. Not sure if its oil, fuel, or according to Peterbitl ; soot from the EGR cooler ... is that even possible? never heard that before, that soot can leak into the Coolant from the EGR. Note : the system stays under pressure overnight. The Coolant is not overflowing or overfilling.
Overall runs decent, almost 800,000 miles. Did the usual DPF clean sensor clean/replaced does a burn every 19 hours like clockwork, max Hg 3.2 in last 10 burn history.
If we have to change the EGR cooler ... fine , i am just not convinced that is the problem... anyone ever had this symptom. Coolant is a brown color no smell, no oil separation in bottle test... we are lost

[redtick]

If the EGR cooler is loaded with soot, it cuts back on the amount of heat transfer area which will force more heat to the tubes that are allowing flow and it is cooking the antifreeze. In theory....

[cjcool]

Peterbilt had the end pipe off the EGR , yes its about 1/4 full of harden soot... or coal looking particles .

[Rawze]

(10-08-2017 )cjcool Wrote:  Peterbilt had the end pipe off the EGR , yes its about 1/4 full of harden soot... or coal looking particles .

All it takes is one flake of that hardened "coal" buildup to go through your turbo and it will destroy it. Nothing to play with, I have seen it a dozen times before. It has the same symptoms as a piece of metal going through the exhaust turbine blades.


If the EGR cooler is full of that 'coal' then it needs to be removed and cleaned out thoroughly or replaced while the turbo is still good. Otherwise, it is a time bomb waiting to cost you an additional $3,000 for a new turbo too.

Another one of those "neglected until something expensive breaks?".

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as far as coolant getting soot in it,.. pressurize the system over-night to 20 PSI with the back of the EGR cooler open, a pan under it, and see if there is coolant or a heavy wetness buildup in the EGR cooler the next day. -- If soot can go one way,.. the coolant can go the other. It is all a matter of pressure differences.

If that is the case, it has likely partially washed out your DOC and DPF, is getting into your engine oil, and causing a lot more wear than normal everywhere too. It is also likely caked up soot and carbon deposits in ALL the egr circuits and sensors and EGR valve badly too. ALL of it needs to be removed and cleaned out very well (or replaced) to prevent hardened chunks of carbon form destroying your turbo or an intake valve.


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MOST of the time when coolant gets discolored fast like that, it is a failed engine OIL COOLER, not the egr cooler. It can also be a failed tranny heat exchanger, but the tranny would be full of coolant too. I would check that as well if you have a heat exchanger on the tranny and it is not air cooled.

[cjcool]

Not at all neglected , goes in the shop all the time , DPF was replaced 6 month ago in Fresno, most sensors replaced, EGR cleaned (according to Pete) we maintain it as good as possible once a week all cods read and attended to. Thats why we are surprised it would have that amount of build up. There are no codes at all pertaining to any of this , not EGR/DPF/ nothing. we did the pressure difference ... nothing , no leak into the EGR, no leak at the dosing unit. Thats why we also believe its the oil cooler not the EGR. we dont want Peterbilt to just exchange the EGR and not fix the problem.I also figured oil cooler , but Peterbilt insists on EGR cooler. we also tested the Trany exchange cooler ...its solid.

[JMBT]

He said it stays pressurized over night, how about exhaust gas leaking in from a head gasket leak, also check air compressor

[DKenworth]

If you would show us a pic how coolant looks like, that wood be great. I had oil cooler leak on myISX 870, coolant had black-gray greasy stuff floating on top of coolant. So if u have same, its oil cooler. Mine fail about 900k mileage, if you going to change it, make sure you change oil termostat too.

[Waterloo]

Get a block test kit from Napa, they stock them. And then de-mandate?.