Oil pushing out the Coolant reservoir and in rad

[JoesTruck]

2004 Dodge 3500 4x4 5.9 6CYL cummins Diesel
Drove 4 min to store and on the way back no heat.
Got home,looked at the coolant it was low but had oil when I put my finger in,then looked and seen the coolant reservoir was overflowed with nice thick black diesel oil.
Never overheated then or ever in it's lifetime. No coolant in the oil,just oil replaced coolant.no smoking,clean exhaust,No coolant smell and runs great still,no oil into the exhaust,just the coolant reservoir and some in rad????
Was thinking blown head gasket,but might be the oil cooler????
Anybody seen this issue before. Any way I can tell if there is a breach in the oil cooler first????

 

[18CrewDually]

You're on the right track. Oil cooler or head gasket.
Here's a youtube video of a guy that lived it. He shows how to test the cooler too.

Oil in the coolant, Fixing the head gasket in my cummins diesel pickup truck

First I fixed the oil cooler, that didn't fix the oil in the coolant so then I tackled the head gasket

youtu.be

 

[JoesTruck]

Got the oil cooler pressure tested and shop said it failed in 3 places.
I'm up in Canada trying to source out a new oil cooler but the parts stores can't find any suppliers,
so that leaves me ordering online. I have a 3rd gen 5.9L cummins and need to know if the oil cooler
is the same match on all gens for the 5.9L cummins or if I have to only buy the 3rd gen.Does it matter,
they are the same block or is there a difference in the mounting,bolt holes,gaskets,alignment ect on the blocks?

 

[18CrewDually]

The kit you're looking for would be 2003-2007 I believe.
Everything I'm seeing for kits are 93-02, 03-07, & then 07.5-up

03-07 Cummins #3959031

Cummins Replacement Engine Oil Cooler 03-07 Dodge Ram 5.9L Cummins

Check out the deal on Cummins Replacement Engine Oil Cooler 03-07 Dodge Ram 5.9L Cummins at Diesel Power Products

www.dieselpowerproducts.com

 

[JoesTruck]

At this point I ordered a new oil cooler and new gaskets,had them sent,got them installed. The old oil cooler failed pressure test in three places. I have been flushing the cooling system,fill drain a few times,then fill with water and dishwasher detergent,I have done that 4 or five times. When I run it I keep getting thick tar like oil rising to the rad cap. I can't tell if it's fresh oil still entering the coolant or the oil that flooded the system. The coolant reservoir was overflowed with thick tar oil,so I know the rad fins and heater core would have been full. I don't notice the dip stick getting lower and no water is entering the oil. I'm hoping there isn't a breach in the new oil cooler or gaskets. Anyone had to flush out thick tar oil from theirs before and does it keep coming till it's flushed 100 times lol?????

 

[JoesTruck]

Scoop on the end is it took over a month to get the thick tar oil flushed and ready for hoat coolant. What a mess that stuff made all over and it took 30 def jugs of water and tar a day for a month. I drained it,filled it with water and dishwashing detergent,would run it for the day,then drain the next day and fill n flush all day. Over a month to clean it up. It's running perfect now. It cost $2000 for a new oil cooler and I got a deal online for one,the shop was going at $180 an hour,this job would have been at least 80 hours in a shop,it took me way more hours. Not a fun ride but got it fixed.