Volvo D2-75 Turbo

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Stainless steel conducts less heat than steel. So it is less likely to overcool the exhaust and create condensation. I had the Stainless elbow for 5 years and it still looks perfect when i checkt it last fall.

Indeed 5 years is a long enough period to prove the correct solution. Thank you for confirming.
In my case the waste gate miraculously did not seize up despite the elbow design but the wheel did. I noticed that the engine lost its power and was not able to accelerate it above 2000rpm. Additionally the oil start to come out of the aircooler bottom.
I found a correct SS elbow with an appropriate space reserved for actuator and got rid of the old one. But still the oil leak seems to be present and I doubt it is due to a blow by. My guess it is caused by excessive oil pressure inside of the turbo cartridge or vacuum on the side of air compressor. The excessive oil pressure because of obstructed drainage and most likely its a return pipe involved that comes from below of the turbo cartridge.

 

[Firebrick]

Ok, in my case the excessive oil deposit was from a loosened bolt on one side of the oil drainage outlet at the bottom of the turbo’s cartridge. The oil leaked was mixed with a tiny amount coming from the air-cooler and introduced a lot of confusion. Additionally, I guess, it may also let to bypass the seals (as the volume of oil pumped was replaced with air through the gap) and instead of evacuation was penetrating to the hot and cold turbo compartments adding additional deposit in its hot chamber and in the air-cooler.
Hope it may help others struggling with a similar problem.