RTnDL

Should the ring seals on the shaft of a K04 turbo seal air tight or should they allow the air to seep through on a pressure test? I have a set of new K04 turbos just recently installed and I have oil in both the intake and the exhaust. I pressure tested the turbo compressor housing and found the air seeps past the compressor side shaft seal and exits through the oil lines. If I plug the oil line with my finger as the regulator is only set at 3-5psi the air then seeps by the exhaust shaft seal as well into the exhaust housing of the turbo. The only thing I can figure is maybe the seals expand as the turbo warms up. But if this is the case that the seals do expand then what I don’t understand is that when oil is found in your intercooler lines it is a sign of failing turbos due to bad seals on the stock K03's so wouldn’t they leak the same way?

RTnDL

Sorry the pictures are not the best but this shows you how I pressure tested the compressor housing. I also plugged the reference line that feeds the N75. The oil return in the bottom pic is where the air was blowing out. If I hold my finger over the oil return the air then seeps past the shaft seal into the exhaust housing.

2.7Lturbo

dude, oil in your intercooler is not a sign of a bad turbo, and yes, air can seep past the seals, they are oil seals, not air seals, the oil provides the rest of the sealing power.

RTnDL

I understand they are oil seals and if you have an intercooler line full of oil then they are obviously not sealing. This turbo however is blowing enough oil into both the intake and the exhaust to create a cloud a white smoke that engulfs the entire car. I also pressure tested the complete intake system from the Y-pipe before I pulled the engine and that is when I first noticed the air seeping past the seals into the exhaust housing. I also pressure tested this turbo first with the oil lines attached and full of oil but air was still seeping past the seals into the exhaust housing.

2.7Lturbo

should not have pressure tested the turbo, possible damage to oil seals. sounds like you need new oil seals. usually oil in intercooler is from PCV recirc system, but if you have it in the exhaust your turbos are bad. is there any shaft play?

RTnDL

There is not really any shaft play as the turbos are new. A little background on this project is that I installed these turbos just a couple weeks ago but after I finished the install I had no boost. That was when I pressure tested from the Y-pipe and noticed the air seeping into the exhaust. It was a low pressure test 5-10psi which I would not think would have damaged anything as K04’s commonly produce 22psi+ when boosting. The boost gauge in the car held the same 5-10psi as the regulator and the air seeping past the shaft seal into the exhaust was minimal so this did not explain why the new turbos produced 0psi boost. At this point I pulled the downpipes to check the turbos and found the oil that I was pretty much expecting to see from all the white smoke. The turbos appeared fine as they spun freely with no shaft play and the wastegates were securely closed. I started the car with the downpipes off and verified both turbos were spinning properly at idle. I also bypassed the N75 with a MBC in the case that something may be wrong with the new K04 flash but I still had 0psi boost. I was running out of ideas at this point of why I had no boost so I decided to have my wife give it a little gas so I could verify the wastegates were not opening prematurely. As soon as she gave it a little gas the right turbo completely seized. Once the turbo had cooled back down I checked the shaft again and it spun freely with no evidence that it was ever seized. So apparently this was the issue the whole time of why I had no boost.

Now I just pulled the engine back out and my concern is why I have oil in both downpipes. That is why I was pressure testing just the left turbo this time which was spooling fine. The right turbo is the one that was seeping by on the original pressure test and is the one had seized so I have a core replacement to rebuild this brand new turbo. I am guessing the left turbo seals were damaged as well during this whole process but I am not sure why. I have never heard of a low psi pressure test like this causing seal damage as pressure testing the 2.7t is not uncommon. I am not sure what caused it but basically I was just verifying that the seals in this left turbo are indeed bad as well. I remember reading once that turbo shaft seals are dependent on the pressure of the air on both side of the turbo so both the compressor housing and the exhaust housing would need to be pressurized enough to push the seals inward to properly seal. If this is case then the oil in my exhaust may have been caused by the pressure test since there was no pressure in the exhaust housing to force the seal inward. I don’t know if this actually applies to this style of turbo or not but that was the whole reason of this post originally.

SloopJohnB@mac.com

General rule is if you rebuild one turbo you should rebuild both.
Unless you like pulling engines.

2.7Lturbo

your problem is not the seals, its the bad turbo, right one is probably fine, left one was seizing.

the pressure test does not damage the turbos with low pressure, but remember, a ko4 making 22 psi, is putting that into the engine, not back into the intake of the turbo so the pressure seen at the seals never approach that high.


Should have gone ball bearing :/

RTnDL

I am getting pretty good at pulling this engine though, lol. I would definitely rebuild both turbos on a normal failure but these turbos are both brand new with maybe 30 minutes of combined runtime and have never even produced boost.

RTnDL

Yes this is very true, that is why I was sure to keep the regulator at 10psi or below.
I would have much preferred ball bearing but I just couldn’t justify the cost.