Oily film on charge air tube near intake clamps

[Mark Rinker]

I have been watching an oily film with sooty streaks develop around and away from the two clamps that keep the blue charge air tube connected to the intake plenum on my 2006 LLY.

Anyone else have this happening? Never seen it this bad on our other trucks, if at all. Clamps are tight, hose hasn't come loose, but is obviously leaking. My first theory was that it came from the previous owner, who was running a Superchips tune while towing. After putting on about 15K miles on stock programming, it appears to be getting worse.

Wiped it all clean today and will watch - I think it is also time to block off the EGR because there shouldn't be that much soot/oil in the intake charge air!!!

[DmaxMaverick]

That oily stuff is from the crankcase vent, not the EGR. The EGR doesn't help, but there should be no "oil" coming out of it.

You have a leak at that connection. Remove the hose and clean up with brake cleaner. Reconnect it and torque properly. If the leak returns, it will need sealing. You could seal it right off and be done with it, but you may destroy the hose getting it off the next time.

[Mark Rinker]

Where is the crankcase vent located?

[phill0072]

in my o6 van with lly I have 1 very light streak at the aft hose clamp but what I noticed the most is on the blue hose is a very light oil film which I wipe of at every oil change (10k) and it comes back, it has been doing it since it was new. when I idle in the summer time the oil film is thicker it actually has little oil beads sitting on the hose "real small one's" I was told by a tech it is oil vapor from the crankcase as this system recirculates the pcv back in to the intake via the cac. I guess it makes since but I don't like the idea of all that oil going though my cac and intake plentum. van now has 126k on it and it has not caused a problem yet and I don't use any oil between changes, and hopefully never will. Will someone please tell me if what the tech told me is correct and should I worry about it thanks.

[Mark Rinker]

Pollution Solution? I don't like my shiny new Duramax with under 40K miles to be eating its own poo...

http://www.maesco.com/products/racor/r_ccv_intro/r_ccv_intro.html

[Duramaster]

Mark,


there is a bulletin for the oily residue. It is a natural occurance which is caused by the closed PCV system. Anyway, clean the boots where they seal onto the turbocharger, pipes and the CAC. Apply P/N 2-90067-801-0 (ISUZU) or GM P/N 90067801 (same stuff) to the pipes, turbo and the CAC and then reassemble. GM says to let set for at least 4 hours. Lots of luck. ;)

[cabletech]

Where is the crankcase vent located?

It is plumed in right before the turbo inlet (under the black thing with 6.6 on it).

Jay

[Mark Rinker]

What would the effect of venting to atmosphere be, aside from the environmental? Would I see any codes set, or detrimental outcome?

[phill0072]

mark, good ? I was thinking of doing the same thing. I can't see it hurting anything as the old gas and diesel trucks vented it into the air, if you do it please post so pics so I can see how it's down.:D:D

[Duramaster]

If you are going to do that, keep in mind that the LB7 had a vapor/ oil separator in the PCV draft hose. If you run just a straight hose to the atmosphere, you may end up with an oily mess as well as crankcase vapors!! ;)

[Dakster]

What would the effect of venting to atmosphere be, aside from the environmental? Would I see any codes set, or detrimental outcome?

A large fine from the EPA....

There are kits to catch the oil and filter the vapors out... You run a hose to a cannister and it catches the oil blow-by. May need emptying between and at oil changes. I don't have the link handy, but it was something I saw when I had my Ford. Some air cooler weere filing up with oil, not real good for heat transfer...

[Mark Rinker]

Yep, like this one posted previously -

http://www.maesco.com/products/racor/r_ccv_intro/r_ccv_intro.html

[More Power]

If you're going to do it, the LB7 system would be my choice. The LB7 came with a crankcase vent system that included a condenser to allow the oil to condense, then drop back into the pan. In theory, only the gases vent. If the LLY doesn't have an oil return fitting on the aluminum crankcase, you'll have to add one.

Another thought.... An oily coating also impacts heat transfer in the charge air cooler...

Jim

[Mark Rinker]

I called an priced out the Racor filter mentioned previously on this thread. Would be about $350 complete with hoses. Doesn't include oil return line - they claim that you can use the unused dipstick tube provision as "there is one on each side of the engine". Thought I'd verify that before taking the plunge as it is of no use without an oil return - even though the return volume is very, very low.

This truck has now been properly baselined in stock trim and will start to get a few modifications here and there - mostly to increase towing power while maintaining or improving fuel mileage.

I'll pull the IAC tube first and take a look to see just how much oily deposits are forming before jumping into the filtration project.

(It would probably benefit more from $300 worth of addition FUEL filtration first...)