Question about AAZ (Diesel) turbo oil feed volume

[Gnarlodious]

A few months ago I had my turbo rebuilt, but after a few short drives I noticed oil coming out the boost pressure tube. Now 3,000 miles later it is pretty bad leakage. Is there supposed to be a restrictor in the oil feed to limit the volume? Because I seem to recall reading about it when I built my engine seven years ago. Is oil blowing out the spindle a symptom of too much oil pressure inside the cartridge? It didn't happen with my old turbo so I wonder what could have changed.
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Vanagon ’83 diesel AAZ w/Giles injection, 5spd 4.57R&P+TBD and a '78 diesel Rabbit

[MarkWard]

I don't know of a restrictor, but on high mileage engines, a new turbo would get a new supply line. Probably best to contact the rebuilder. Someone else will comment on the restrictor if there is one. How is your oil return? How is it plumbed? A restriction on the return could be a problem too.

[zuhandenheit]

Dumb question: are you sure it's coming from the turbo and not PCV?

[Gizmoman]

Might want to check your drain?
https://youtu.be/ESBc0bruGZo
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82 Vanagon Westy - AAZ 1.9 TD, HE200 Holset, WAIC, 27.75 dia tires, Electric power steering, 5-speed AAP w/.078 5th
Oversize spare carrier - stock location (no longer for sale).

[ALIKA T3]

Disconnect the PCV from the intake, put it to atmosphere.
Clean everything.
Drive.
See if the turbo compressed air hose is getting oily again. If it is, your turbo seals are bad.

I went through many CHRA's before getting fed up and used a 30 years old turbo to solve this issue.

Then Borg Warner started to re-make the K14 available again, installed it, no problem....

Quality is key....
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Silicone Steering Boots and 930 Cv boots for sale in the classifieds.
Syncro transmission upgrade parts in the Classifieds.
Subaru EJ22+UN1 5 speed transmission
http://www.thesamba.com/vw/forum/viewtopic.php?t=416343
Syncro http://www.thesamba.com/vw/forum/viewtopic.php?t=4...num+gadget

[crazyvwvanman]

VW Parts shows a restrictor orifice threaded into the oil filter mount passage for the turbo oil feed line section.
AAZ, 1Z, AHU
Called a "choke" in some places.
Threaded into the oil filter mount on the BLOCK side of the oil feed hole for the turbo.
The oil filter mount must be removed from the block to access the restrictor.

Mark

[ALIKA T3]

I read about this restrictor before, there's some lengty discussions found on a couple forums.

I thought it was to keep oil in the cylinder head for start up? From my distant memory, it's not on the turbo oil feed port , even indirectly.

Worth researching more in-depth than trust my memory
_________________
Silicone Steering Boots and 930 Cv boots for sale in the classifieds.
Syncro transmission upgrade parts in the Classifieds.
Subaru EJ22+UN1 5 speed transmission
http://www.thesamba.com/vw/forum/viewtopic.php?t=416343
Syncro http://www.thesamba.com/vw/forum/viewtopic.php?t=4...num+gadget

[MarkWard]

Well that's convenient to check for. It also looks like it could gum up pretty easily. If someone could document the ID of the orafice and external one could likely be adapted and it could be visually checked from time to time.

[ALIKA T3]

[skills@eurocarsplus]

on the 1.8T I'm 99.9% sure that restrictor is in the port for the turbo oil feed. I remember taking it out while cleaning the oil filter stand

That said, every turbo I have dealt with has always had some oil feed restrictor

remember, the turbo seals are nothing more than mini piston rings so having a ton of pressure here wouldn't work well.
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[Gizmoman]

A larger, less restrictive drain line would significantly reduce pressure. However, you said that you didn't have this issue before the rebuild, so I might suspect the rebuild. How confident are you in the work that was done?
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82 Vanagon Westy - AAZ 1.9 TD, HE200 Holset, WAIC, 27.75 dia tires, Electric power steering, 5-speed AAP w/.078 5th
Oversize spare carrier - stock location (no longer for sale).

[?Waldo?]

I've run several of the VW turbos without any restriction in the feed line and without any issues whatsoever. That includes the AAZ K03, AAZ K14, AHU K03, VNT15, VNT17, etc... Ball bearing turbos (none of the VW turbos are BB) require a restrictor in the oil supply, but journal bearing turbos (as all of the stock VW turbochargers are) do not require any sort of restrictor as the clearance at the journal bearings IS the restrictor. The restrictor that crazyvwvanman shows that VW added to later filter housings does not limit the oil flow more than what the clearance at the journal bearings will intrinsically limit. I can think of a couple plausible reasons why VW added the restrictor, but none of them have anything to do with limiting the amount of oil flowing to a properly functioning turbo. If the turbo is leaking it is not because of a lack of oil supply restrictor. It wouldn't hurt to add the stock restrictor, but there is zero chance of any sort of pressure buildup at the turbo shaft seals even with full oil flow unless there is some other issue (e.g. clogged return line, poor routing of return line, etc...).