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ClickClickBoom ClickClickBoom is offline
Caveman Hammer Mechanic
 
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Join Date: Feb 2009
Location: Boulder Creek CA
Posts: 3,055
Garage
Hello,
I originally come from the aircraft world, pistons and turbos specifically. You have a very nice example of coking, not cooling your turbo off before shutdown is the most likely culprit. Those bits come from the center section of your turbo and flow from the outgoing oil into your scavenge system then to the sump. If you are using a full flow oil filter that has not clogged and started to bypass the pressure side of your lubrication system is safe, if you are bypassing due to clogging and/or excessive oil pressure you are gonna have issues, those carbon chunks are hard, harder than dirt and work wonders on bearing materials, ie improving clearances! Check your upstream oiling areas(intake valve covers) for more debris, it will be silty(the worst) if there. If present, buy a 55 gallon of oil and flush your engine repeatedly, until the debris is removed. Replace your oil filter as soon as the oil starts to discolor and you might be able to get most of it out over time. The only long term prevention is turbo cooling time, I do not shut off my turbo vehicles(2) intil the egts show below 300F post turbo. Been operating the same turbo for more than 15 years in my truck. I have had A/C turbos last through 2 engine overhaul periods before needing an overhaul, but the A/C community is more fanatic in general about the turbo cool down period due to the insane costs of A/C parts.
Good luck
eric
Old 02-21-2009, 11:56 AM
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