I have a black line around the top of my degas bottle,what could this be from.

 

Does it have a oily look to the top of your coolant or smell like fuel a bit

 

Coolant looks clean no oil or smell, truck is a 2000 with 118,000 miles on it.

 

I had the same thing on my truck.

First I had my oil tested at Blackstone - thankfully with negative results. Potassium or sodium levels in the oil would indicate coolant in the oil.

Second, since I am new to the truck, I didn't know if the "soot" was residual from a prior event or symptoms of a new problem. I drained enough coolant (into a clean bucket to put back in) and removed the coolant bottle which I cleaned with soapy water. I could only get a rag into the first chamber so the other three chambers had soot which I couldn't remove. My goal in doing this is to see if the soot returns (which thankfully it has not).

Third, I put on a Dieselsite coolant filter.

Finally, I checked the oil dipstick for irregularities (which I did not see).

I'll try to post pictures later on.

As an aside, my oil cooler orings were recently replaced. I'm sure others will chime in and suggest that oil - coolant crossover often occurs as a result of deteriorated orings in the oil cooler.

Good luck.

 

Hmmm.... Did it look like this?

 

Yes it looks just like that Tugly.

 

Pictures of my degas bottle before cleaning:






Except for clear condensation, my degas bottle is clean at this time.

Although I forgot to mention it above, I did pressurize my coolant system to 15psi and I didn't see a pressure drop over the 15 +/- minutes that I kept the pressure on. In case it helps, A/Ox4 puts out a YouTube video on how to pressure test the cooling system.

Unless the soot returns, I'm going to assume the soot was from a residual problem. If I were you, I would do the same.

I think the other thing I read about when researching the issue was the potential for cracked injector cups. I believe you can test that by removing the injectors and pressurizing the coolant system. Unless the soot returns, I don't think it's necessary to go there.

 

Well.... If it's that... the problem is not easy, or it's really terrible:

In my case, it took two problems in conjunction to get soot into the degas bottle.

1. Leaking copper washer on the injector nozzle or a loose injector.
2. Cracked cup below the injector fuel O-ring.

The "epic" saga is in the injector cup link in my signature.

The really-terrible: It could be a blown head gasket, but these are extremely rare.

Are you getting loud injector knock, bucking and jerking at just the right throttle, and really smoky startup?

 

No smoke on start up no knock truck runs good,I think I'll clean the ring off the degas bottle and put a new coolant filter on an see what happens.