Originally Posted by dredman
so the tech pulled the turbo tubes, and oil in both, so he is ordering a new one. He is convinced the oil is coming from the breather and won't listen to me, as it is coming from BOTH sides of the engine. I don't want to piss the guys off, but I do want to know how long the new turbo will last - another 150 MILES?
Oil in both turbo tubes is very telling. When mine popped (and this particular ISX Cummins had an appetite for turbos), oil was *ONLY* found on the "boost" side. Now if there's oil on the air-filter side, it could conceivably be from the failed turbo, but I'm not so sure. This guy could be right in that oil may be coming from the breather. I have no way of knowing his experience and knowledge. But here's the thing...
Many engines have breather tubes that would relieve internal crankcase pressure as relayed by Christopher and his Peugoet. In years past these were simply open to the ground, but emissions laws forced engine designers to eliminate this. So, many systems direct this back into the intake system, where these gases can be burned. With sufficient age and wear, some oil will enter this system and travel through the intake system and get burned as well. This would account for a small amount of oily residue in the system.
Just for those who may be curious as to why my ISX Cummins went through so many turbos ... according to my local guy, it had something to do with the EGR system and soot buildup with age and other technical things way above my pay grade ... in short, it was a bad design and in subsequent years of this engine, it had been reworked to correct this issue. An EGR bypass kit was available (legality is questionable) to work around the problem. The truck was later wrecked and scrapped.