oil leak in coolant tank and part identification of dd15 engine.

Oil in the coolant is usually a failed oil cooler. Most engines it isn't a terrible job. Not totally familiar with DD, but looks like a centrifugal crankcase oil separator. You are probably seeing blowby gases, steam from here as it vents to the atmosphere.

 

1. I’m not sure what is called, but it the EPA version of a blow by tube. Basicly it’s a centrifuge that throws the oil out of the blow by vapors, puts the oil back to oil pan, and gassed into air.

2. It’s possible that the “centrifuge/ blow-by filter” isn’t working or is gummed up, but it should throw a under speed code / check engine light. With out looking at it, I couldn’t tell, it maybe time for an in frame, or it could be as simple as replacing the “blow-by filter”. Your oil in the coolant resovoir could be a leaking coolant/ oil filter housing. It might not hurt to have the fuid tested, sometimes Exhaust in coolant can look like a dark oily residue, which would suggest an EGR cooler.

3. Blow-by filter- $500-750 ( have never replaced one, but they are simple to replace.
Oil/coolant housing- gasket/seal roughly >$100. But with that many miles it will probably have erosion so the entire assmbly would be needed. For $500-$750. And around 2-3hrs labor. (Maybe have never actually priced this)
EGR cooler (if needed) is $1800-$2000 simple to replace 1-2 hrs labor.
In-frame- i’ve Seen on this forum anywhere between $18000 to $25000. Which is probably $8k-$10k in labor and about the same in parts.

The DD15 is suppose to be a million mile motor. Depending on how the previous owners/drivers used it, it maybe good enough for part time use as is. Or It could have 500,000 mile of Hwy use as is. But if it needs the In-frame and you find a good, clean, and knowledgeable mechanic to do the work, you should get another million out of it.

 

I would love to give you a definite price, but @ is as close as I can get. Depending on where you take it, replacing the seal/gasket behind the oil/coolant filter/cooler housing is would be roughly $50-$100 dollars for parts, @1-2 hrs labor. Most OEM repair shops are running $100+ per hr. So $300 should cover it, but with the age of your engine, you should have $1000 ready to spend for just oil/ coolant housing repair. Depending on how the coolant system was serviced (or lack of) over it’s million miles, you should leave open the possibility that the aluminum housing may have eroded through electrolysis leaving the housing un-usable and needing replaced. In that case you could be looking at $1000 or a little more to buy a new housing with labor for the repair.

The EGR leaking can leave a dark residue in the coolant system. This residue is carbon/exhaust, but can feel slick like oil to the touch and could be mistaken for oil. So I was just covering all bases.

The code on your video pertains to a heater/air conditioner temp fault.

And yes, if you have a broken ring causing the smoke/ blowby, it can get real expensive. With the mileage on your motor (and no known history) your looking at a complete overhaul / inframe. At a minimum your parts an labor will be @$15000. If you start adding things like a new turbo, new/remanufatured head/ etc. your getting closer to a $25,000 to $30,000 bill, And I would suggest purchasing the warranty if possible. Just to cover yourself. A lot of things have to go right to get a good overhaul, warranty can help with the burden.

 

The blow-by filter is the centrifugal crank-case oil seperator as mentioned by Heavyd. I just couldn’t think of the name of it at the time.

 

The crank case oil separator spins at 1000 to 10,000 RPM to knock the oils (and possibly other fluids/solids/vapors out of the air escaping the crank case. Making it as clean as possible.
They say if you see any oil on it or coming out of it, it isn’t working. There is a speed sensor mounted in the top. If it isn’t spinning (not working) the engine computer will throw a code and should kick on the check engine light. Which the code that you show active doesn’t confirm that.

I’ve been around many DD15’s but none much over 500,000 miles. At the beginning of this thread I could see a scenario where this breather wasn’t spinning fast enough, not working, and/or not cleaning the gasses escaping while the engine was warming up. It’s still a possibility, and this breather is simple and easy to replace ( if you can get to it) and maybe something that would be of a “low enough cost” to try to replace yourself before sending it into a shop for a rebuild/overhaul and is a part that will probably be suggested to be replaced by the shop that does the Overhaul.

It maybe a long shot, but it’s possible.