[ausjohn]

Replaced radiator and all hoses pressure and vacuum test cooling system
Cooling system and Expansion tank flushed out twice , Brown Orange Hoat scum from mopar coolant but no (blackish soot) in Expansion tank.
Over 12 week blackish SOOT build up in Coolant tank no diesel smell, coolant loss 100 ml
coolant Clean.
DPF burn temp okay data log engine temp okay
Combustion gases no positive test in cooling system ?
engine oil okay

 

[Deertraker]

Soot?.....Interesting. I had OIl dumping overboard from the expansion tank...2-4-cups of it. Parking spot a mess. Investigation found OIL COOLER on driver side of engine (below oil filter) was leaking OIL into COOLANT. The oil pressure is much greater than the coolant pressure so it sent oil OUT rather than Coolant IN.....
Oil cooler is hard to find at this time and costs $500. The cooling system was flushed with dish deterg about 4 times and water 5 times. Still gets a slight oil sheen on the coolant tank.

 

[ausjohn]

Soot?.....Interesting. I had OIl dumping overboard from the expansion tank...2-4-cups of it. Parking spot a mess. Investigation found OIL COOLER on driver side of engine (below oil filter) was leaking OIL into COOLANT. The oil pressure is much greater than the coolant pressure so it sent oil OUT rather than Coolant IN.....
Oil cooler is hard to find at this time and costs $500. The cooling system was flushed with dish deterg about 4 times and water 5 times. Still gets a slight oil sheen on the coolant tank.

I found that the good quality hose i used was not compatible with cooling system it was not designed for heater radiator use, it was breaking down. This hose vents back from thermostat back to the expansion tank. still have to check and flow this through.
.
,

 

[ausjohn]

I found that the good quality hose i used was not compatible with cooling system it was not designed for heater radiator use, it was breaking down. This hose vents back from thermostat back to the expansion tank. still have to check and flow this through.

I found that the good quality hose i used was not compatible with cooling system it was not designed for heater radiator use, it was breaking down. This hose vents back from thermostat back to the expansion tank. still have to check and flow this through.
.
,

Yes the blackish scum soot is internal combustion engine in coolant it seem to be a minor head gasket leak.
I used Nulon Permanent Head Gasket Repair with DuPont™ Kevlar® fibre & liquid resin provides the ultimate strong long lasting fix. Formulated to permanently seal