A bit of warning, this will be long winded. TLDR below. I picked up a 2012 f250 PSD a couple months ago, its got 150k and is deleted and tuned. It's a one owner Florida truck with all scheduled maintenance done at the local Ford dealer and no accidents or mechanical issues shown on the history. It's one of the cleanest service records I've come across in a used truck, a big factor for me buying it.

Now the issues... After about two weeks it started to puff white smoke from the exhaust, typically when up to full operating temp and taking off from a stop. Under throttle the smoke would clear and would normally not appear again until I stopped and took off again.

So far I've physically deleted the EGR with block off plates and replaced the turbo with a new Garrett factory replacement unit. I also replaced all the associated gaskets, lines and fittings.

The truck seemed fixed after the new turbo, it had zero white smoke or haze. But after about 3 weeks the symptoms returned. I went to pull the turbo off to send back to Garrett for warranty, but when I got to the turbo it still looked new. Zero axial shaft play, no wheel contact with housing, and no oil in the charge side. I now think that the issue isn't turbo related. I put the truck back together and started diving into the coolant and PCV system as I've read they can lead to white exhaust smoke.

My primary reservoir holds 15psi all day long under hot and cold engine temps. I do believe I have a leak in the secondary system, but so far I'm not sure because my pressure tester doesn't really seal that well on the degas so it's hard to get a solid reading.

My discovery, today I took the truck out and ran it until it got up to temp and started smoking then I pulled the oil cap and let all the crank case pressure flow freely out, the exhaust stopped smoking shortly after. I took the truck around the block without an oil cap and the truck didn't smoke. I got back to my house and put the cap back on, before I even got to the end of my driveway it started smoking. I pulled the cap again, took if for a long drive (without the cap) and it didn't seem to smoke... I feel like I've been able to narrow my issue down to a PCV system issue.

Now my question, when I pull the hose off of the oil separator AND the cap off of the oil fill neck, the flows are not equal. The oil fill cap has much more flow, should they be equal? When I researched the inner workings of the oil separator, there appears to be no filter or valving inside, just passage ways. Is it likely that the oil separator has clogged? Has anyone run into this issue?

I want to avoid the CCV delete with vent to atmosphere, I don't care for smelly gasses and oil drippings. I'd prefer to fix the problem and leave the OEM CCV system in place. My hesitation with just replacing the oil separator is that there just doesn't seem to be anything inside of it to fail, but that may be my next move. Any thoughts? Is there something else that could clog and would restrict the CCV?


TLDR: Truck smokes white out of the exhaust. Already replaced turbo and deleted EGR. Truck doesn't smoke with oil cap off, but does begin to smoke almost immediately after putting the oil cap back on. Clogged CCV? Is that a thing?

 

Definitely seems to be a crankcase ventilation problem. It's my understanding that the 20's have a different design CCV, but that earlier models (2012 included) plug up and are a replaceable item. https://www.dieselfiltersonline.com/...ent-valve.html

If you don't want to vent to atmosphere, replace the CCV and also install a Mishimoto catch can kit to intercept the oily goo before it the vapors go through the CCV.

 

Thanks for the info, I wasn't aware that they could plug up. I just ordered a new oil separator, we'll see if that works. If it does I'll probably get the Mishimoto catch can to help keep this from happening again.

 

Or alternatively just replace the CCV whenever it plugs up. The advantage of the catch can is it keeps the crap out of the CCV and the intake.

 

It may just be the tune.

 

At first I considered the tune, but the fact that the truck ran perfect without smoke for 3 weeks makes me think that it isn't tune related. If it was it would have been doing it the whole time. I'm picking up the oil separator today after work, so I'll have an update if it works or not soon.

 

Hey jolly, where did you get that info, about the filtered CCV boxes for early models? I was under the impression that the filtered boxes didn't come until the 17s.

 

From their website here:

https://www.mishimoto.com/ford-6-7-p...2011-2016.html



All this has me curious about the CCV boxes and the different years. I'm gonna look into this.

From here :

https://www.mishimoto.com/engineerin...00458#continue



So may be your box just got clogged up with all that crude and the heat turning it into solids clogging up the passage ways.

 

It’s possible I had that backwards. The 2020 CCV is another new design, right?

 

I'm not sure to be honest. I heard that the new design with filters had problems because the filters would jam solid and pop the silicone relief valve that is there just for that reason allowing bypass to just pour into the intake. I also heard stories of engines blowing off oil fill caps because of this. I'm not sure but I'll check and see if Mishimoto has a catch can for the 20s because I don't know if they are the same as the 17 to 19s.

 

Okay so apparently the 17s and up oil can system is used for the 20s.

https://www.mishimoto.com/ford-6-7-p...-kit-2017.html

 

So, some unfortunate news. I installed the new oil separator yesterday, it did reduce the amount of pressure coming out of the oil fill neck, so I do think that the old one was clogging up. What sucks is that the truck still smokes... It seemed to be fixed for a little while, but the first time I hit full boost and then came up to a stop light, it began to smoke. Once I got to where I was going I had to pull the oil cap and hose clamp a shop rag around it. It still doesn't smoke as long as their is no oil cap.

I'm running out of ideas... I don't know what else could cause the truck to react like this, especially since it only happens under specific conditions.

My only thought is that the oil separator was so clogged that it caused the new turbo's exhaust seal to fail due to elevated oil pressures... I just have a hard time believing the seals could fail that quickly, its been less than 1k miles and the blow by isn't that crazy... It looks like I'll be taking it back to the dealership and have them try and diagnose it, if they can't find anything idk what else to do but to either warranty or replace the turbo.

 

That stinks. Do you have the ability to adjust your tune at all? Do you have any idea what kind of changes were made to turbo boost and/or vane position vs stock? (I've tuned Duramaxes but never tuned a powerstroke, so I'm not sure if what I'm talking about is even applicable.) What I'm thinking is that if the vanes are closed down too much your drive pressure might be causing excessive blow by? Deleting the EGR would only make it worse.

 

Any chance it's coolant in the exhaust? Any way to smell the white smoke to see if it smells like oil or coolant?

 

I don't know anything about the tune, it was deleted and tuned when I bought it. It's possible the tune has something to do with it, but I'll be honest that I don't think the blow-by it has right now, at idle, is that extreme. I've seen videos on youtube of much worse situations than mine. I can flip the cap upside down on the fill neck and it'll bobble around but not get blown off, as long as I give it a back board with my hand since the fill neck isn't level on the 6.7.