(01-25-2019 )Rawze Wrote: I have also seen repeated turbo failures if there is chunks of carbon buildup in the egr cooler, the egr valve, or any other exhaust or egr circuit.
You say it has oil leaking into the exhaust manifold. This will get into the egr cooler + egr valve and make diamond-hardened chunks of carbon (hardened soot from the oil and heat). - Later, these chunks of hardened carbon will come loose and make their way into the turbo exhaust housing one way or another and cause problems like destroyed exhaust impeller, damaged VG housing and packing in around the VG ring, limiting its movement.
I have seen guys destroy several turbochargers in a row in only a few days time due to this problem alone.
The solution is to replace the egr cooler or at least pull it off and clean it out really well with heavy solvents to remove the chunks of carbon/soot. - Either way, it has to come off.
Also, if the egr cooler is impacted, the egr valve, egr piping, and intake needs the same treatment to remove all of it. - Sometimes a truck will run for so long with oil seepage + carbon issues that it will even build up behind the ecm in the head around cylinder #2 real bad and cause the engine to run unbalanced under load.
A chunk of carbon in the egr cooler, intake, or egr circuits is not worth destroying a turbo, so I generally tell others to just replace the egr cooler if it looks like it is packed with carbon + clean out everything egr, exhaust,intake -related really well including removing the intake manifold and checking the intake of the head itself if necessary. Once a problem with carbon chunks happens, it gets everywhere in those circuits and it is hard to get it all out. -- It only takes a single missed piece of it lurking somewhere like the CAC or other place for yet another turbo to get destroyed.
- How can it get from the egr cooler around to the cac? -- every time you shut off your engine, your turbo does several 'cleaning cycles' for the vg ring. If a person listenes closely, they will hear all kinds of "fauf, fauf,fauf" sounding turbulences occurring while the engine is shutting down. Air flow goes in multiple directions in the egr, exhaust, and intake circuits. Some trucks are worse than others for this, it depends on the design of the CAC, ect. of a particular make/model vehicle.
Thank so much, for such a good explanation on this subject.
