I have a 06 Duramax. For two or three years I have had oil building up under the hood. As you are looking at the motor from the front, Left side at top of big pipe. It's not dripping, just building up. No oil loss on dipstick between changes.
I had it dye tested over a year ago and dealer could not diagnose.
A month ago an independent mechanic dye tested and said it was the Turbo leaking.
He suggested replacing the big pipe under left side of engine because it was saturated with oil and likely to come off.
There seems to be no loss of power. We pull different trailers daily with no evidence of issues.
Could it "run forever" like this?
What should I look for to pre-empt a failure?
Should I replace it?
If I replace it should I replace it with new or used?
The PCV is fed into the turbo low pressure side. A slight amount of oil then travels through the induction tract, very miniscule. You are probably getting a slight seepage out the compressor outlet, it is very common, and usually no particular issue. Nonetheless, it should be pressure checked to be sure you aren't losing boost under hood in any significant amount.
Some seepage is normal, mine does it, as does about every Duramax out there that has not had the PVC reroute. I would not replace the intercooler pipes, seen Duramax's with 700K on the clock that were stock, and never cleaned. If you are worried about the silicon hoses slipping off the intercooler pipes, remove the silicon hoses, clean the oil residue off were they are clamped on the pipe, as the pipe. I used alcohol, then when assembling spray the pipe with some Aqua Net Super Extra Hold Hairspray. Make sure you don't let the hairspray dry before you slip the silicon hose back on, slip it on wet. I have yet to see a truck slip a hose off after doing this. I think GM has some kind of black sealant they use at the garage, not sure what it is. GM will use it on the one that normally comes loose, which is the one on the driver's side of the turbo, near the master brake cylinder.
2007 Fleetwood Excursion 40E Cat C7 350 HP
2007 Chev 2500HD D/A Long bed CC
2011 Toyota Tundra
Gone but not forgotten, 2008 Jayco 299 RLS
Both hot side connector tubes will show oil migration. Not an issue unless getting blow off under high boost. The hair spray trick works, too. Replace any silicone connector that shows sign of delamination. Pressure check is needed if no gauges.
I replaced the hose on the right as it was blowing off under pressure last year. We used the hair spray trick on a new pipe with new clamps. No issues since. The seepage discussed above seems to make sense. Today I pulled back up Saluda Grade from SC to NC wit no issues pulling 28' TT. Thanks