2012 F250 6.7 38K . Checking under the hood I notice my main degas bottle is completely black. The fluid appears to be at normal level and is orange in color. I have no check engine lights and the truck appears to be running correctly. I think it’s exhaust maybe from the EGR, however this is my first diesel and I have no clue how to trouble shoot it.

The only info I’ve found is all on 6.0 troubles. I am attempting to attach a few pics.

Solid black

Pull straight from the bottle

Line from EGR

 

Very interesting. Are you the original owner?
Have you ever replaced the coolant? Checked it with test strips?
Maybe something to do with the additives?
Good that the liquid is clean orange.
Maybe remove the tank, clean/replace and keep an eye on it?
Problem is since the interior of the tank is black there is probably the same throughout the system.
Not sure how to properly flush one of these beasts these days.

 

I am the second owner. I have had the truck for about 8K miles. I had two shops including the local ford dealer look it over before I purchased it. The local Ford dealer also performed the under warranty def heater replacement. While certainly possible, I don't think they would have missed it.

No, I haven't replace the coolant. I have only done on service to oil and fuel filters. I have considered removing the tank and cleaning but I want to know the cause before doing work and spending extra $$. The black doesn't come off with just wiping it. It appears to be stained. Which leads me to think that exhaust might be getting into the tank. The secondary bottle is normal color.

 

My bottle has looked like that since about 2014. Dealer said as long as coolant test good there isn't a problem.

 

I really hopeful someone can help me.
I performed a CO2 test on the bottle using red diesel fluid and the truck running up to temp and it came back negative.
Drained the radiator, the fluid looked okay with a few drops of some type of dark sludge from the bottom of the bottle. Install good looking salvage degas bottle. Did a flush with 4.5 gallons of distilled water with truck up to temp. My newer degas bottle is doing the same thing and starting to show signs of black. Did another CO2 test with same result while the truck was warm. Drained the diluted antifreeze and it is a dark reddish color.

Something is invading my cooling system. I not sure what. Here are a couple more pics

 

Not sure where the black stuff is coming from. I would have the dealer do a flush on the system. I never do this kind of work at home because I dont have and can't afford the tools to do the job correctly. Black stuff is somewhere in the system and needs to be flushed out.
My tank doesn't look like that and I have 62,000 miles on my 15

 

How are your hoses? Maybe they're disintegrating on the inside..

 

my 2013 with 60K on it does not look like that. I agree, a better flush is needed.

If all other fluids are ok,I would suggest a dye in the motor oil and see if it shows up in the coolant system.

 

I'm betting the EGR cooler core or orings from the core to EGR housing are allowing soot to enter the cooling system. I have 107K on my 2012 and the bottle is still clear looking!

 

So I decided to replace my oil cooler and do a simple green hd flush. The flush reviled that there was a good amount of oil in my system. See the pics below. Ended up soaping it twice, then many flushes later it cleared up. A final flush with distilled water then a fill with proper coolant and distilled water.

I have since drove the truck over 200 city miles and the bottle is still clear. Hopefully it was the oil cooler.

I came to the oil cooler after realizing that the oil pressure is much greater than the coolant. While I did not notice any substantial oil loss, a small pin hole could muck up the system. The motor oil is nasty in these trucks. Coolant most likely wouldn’t transfer the other direction because of the pressure differences.

Thank you to those who chimed in with your suggestions, It helped me in the processing of what it might be.

First Flush


Many flushes later

The final result!

 

Interesting. As I am following this, nothing led to an oil cooler issue. But it does make some sense that maybe it was compromised.

 

Thanks for posting pictures and your resolution. It may really help others down the line.

 

I've been following this but didn't have anything to add. This is very interesting. Thanks for the pictures and comments. Keep us updated. I hope the oil cooler was the issue because if so, this would help others down the road if this issue were to occur. Thank you.

 

I thought the oil cooler was separate from the radiator like the trans cooler. if that was the case how can oil get into the coolant? Even the transmission cooler is separate.

 

The secondary cooling system cools the oil, trans fluid and fuel. The oil cooler uses coolant not air to cool the oil temperatures.