Gents,

Time to defer to those that are more experienced. I have a 2007 6.0 that has been smoking, and am currently left wondering if the root cause is a headgasket or possibly a culmination of more than one issue.

I just finished replacing the EGR and oil coolers this past weekend, completing a flush of the cooling system and refilling with ELC. The truck had been smoking and losing coolant prior, which is what initially led to the EGR swap. Replacement parts were the BPD EGR cooler and OEM oil cooler. EGR valve and port were dry during teardown, but the downpipe was completely coated in a gooey/tar looking substance. The issue does not appear to have been corrected with the parts change.

The truck does not smoke at startup, and doesn't start until ECT seems to come up to about the 140* range. At this point it begins blowing a moderate amount of steam/smoke. Thick enough to watch it climb and dissipate, thin enough you can still see through it mostly. Once the truck is in gear and driving, it just billows out during acceleration until the turbo builds about 10-12# of boost, then it rapidly tapers and cuts off. Once it's been on the interstate and driven for a while, the visible exhaust disappears at anything over 2-3# of boost, but returns relatively quickly if the truck comes to a stop. Accelerate again and it starts billowing. I have had instances where there doesn't appear to be any real noticeable visible exhaust when the OAT comes up a bit.

Drove the truck to work yesterday 55 miles, 50 on interstate with a starting coolant level at the min mark. Arrived at work with coolant at min. Drove the truck home and the reservoir was empty. Put 1/2 gal water in this morning to bring it back up to min again, drive to work and coolant is still at min.

Exhaust this morning appeared to start heavy white, turn bluish and then take on a brown tinge before clearing while getting on the interstate.

Truck is running smoothly, fuel economy cruising at 70 is right around 18.6mpg. Doesn't seem to be any noticeable lag, stuttering, missing. ECT/EOT monitored through Insight CTS, delta is around 6* when cruising (ECT 190/EOT 196). CTS is reporting FICM v at mostly around 48.0, occasional dips to 47.5 with random instances of a dip to 46.0. INJPWR reporting at 49.2v, fairly constant. Turbo underboost and Cyl #3 contribution were reported at the first startup after patching everything back together, but once cleared I've not received any new DTCs.

There's never been any puking from the degas bottle that I can tell, although there does appear to be 1 noticeable gurgle about every 30-45 seconds (at least during warmup).

Coolant doesn't smell sweet, or even like fuel. Just smells like typical diesel exhaust, and you literally have to get your face in it to smell it.

Any ideas?

 

Have you tried monitoring coolant pressure? You are losing coolant, and if it's not externally that you've noticed then it is being burned internally. The smoke is an additional symptom, but may potentially not be from a HG. Stating that it clears up when boost is added points to a fueling issue but i'm not sure, white smoke is a failing injector.. black/grey is overfueling

 

Add a gauge to the degas line, pretty simple. Shouldn't be hard, and will prove excessive coolant pressure. If it builds pressure relatively fast, that may confirm head gaskets. If you did an EGR delete, then that would be the only path, through the gaskets. Pull the EGR valve and see if its leaking inside the intake, you may have pinched a seal or something when you put it back together.

If it wasn't loosing coolant, I'd say check your turbo seal. I'd still check that, pull the cac tube and look for oil inside the tube. Steam dissipates fast, oil would be like fireplace smoke... just keeps going upward while slowing disappearing.

You could pressurize the radiator and check for leaks as well. An injector would appear similar, watch for a contribution code. You said no new DTC.... did you get the #3 injector contribution back or turbo under boost P0299?

1) The dry EGR port during tear down...... would have said that the EGR hadn't ruptured.

2) What were EOT-ECT temps that lead you to replace the oil cooler?

3) Smelling the exhaust and it smells like normal may be an indicator of an injector issue.

4) the real catch is loosing coolant.

5) Turbo under boost is 4psi or more for 5 seconds or more of under boost. Clean the MAP sensor and tube, clean EBP sensor and tube and the EGR sensor is new? If the P0299 came back, you need to clean the turbo vanes and unison ring. Sticking turbo can smoke. Watch VGT on the Insight... see if your getting 15 or 84. Its a commanded number, so that may not really show you the answer. Can you get a good turbo fart?

Hope I gave some ideas to start with. My thoughts on what you posted and I'm sure other will chime in.

 

I'll look at getting a gauge into the line to check coolant pressure. I opted to go with the BPD EGR cooler instead of a full on delete, just to keep the truck compliant.

When it's warm out, the vapor is for all intents and purposes invisible, save for a small (1/2 - 1 sec) "blast" occasionally during accel. Drop the OAT to 60 and under and it starts to become more and more noticeable.

1.) Agreed, although wishful thinking encouraged me to push forward

2.) The temps were actually within acceptable limits. Deltas were about 8* on average unloaded. Uphill climbs might see this push to 12* at max. Only time they were ever really spread was the first time I noticed the coolant was low, CTS alarmed for ECT around 226* and EOT seemed to be around normal. Replaced the coolant, they were back in-line with each other. Bought the kit from BPD, figured since I was going to be that far into things I might as well replace another known high-failure part.

4.) Coolant was down again after the trip home today, although not nearly as low as it went yesterday. I was about 3/4-1" below min, yesterday it was completely empty. Both times the truck has made it to work without the level in the degas dropping at all, despite smoking more on the way in.

5.) I've been checking the DTCs continuously, none have been logged in the last ~250 miles since reassembly/clearing.

I did notice while checking the coolant after getting back to the house, that it looks like I have a very small leak running down the back half of the driver side exhaust manifold. Apologize for the quality of the pictures, as it's not an easy place to get a camera into. I haven't had the chance to climb under the truck to see if I can spot the actual point of origin, also on the list of things to do now.

Doesn't appear to be significant enough of a leak to produce any puddles (yet), but has done well enough to coat some small surface areas on components below.

 

It looks like a big enough leak to lose some degas level that's for sure. Passenger side? you'll have to dive back into the truck, going on the assumption that something didn't seat right while the BPD cooler went it.

If you have a leak in the cooling system a pressure gauge will not give you an accurate reading

 

It's actually down the driver's side. I'll be taking a look at it later today, see if I can spot the source.