Boost leak in turbo cause oil seal failure?

madmikeismad

madmikeismad

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So I've been losing sleep at night trying to figure out why the vw won't spool the hx35. It will start to spool, and then just kinda fall flat and maintain that pressure. I pressurized the sytem to 30+ psi and couldn't find any leaks anywhere.

Then I started wondering what would cause the valve cover to literally BLOW oil all over the bottom of the hood, and why it only does it when driving. I can rev it up in neutral and it doesn't seep oil at all.

Then I remembered how the holset was leaking oil out of the exhaust and compressor side, and I fixed it with a bilge pump.

So I'm thinking that the turbo is leaking boost internally into the oil passage, and the extra air pressure leaking into the oiling system and block is causing the valve cover seal to fail, and spew oil everywhere.

Is this possible? It's losing about a quart or so every 400 miles. I'm really hoping this is the cause so that I can fix it when I switch out for the garrett. Since I just now thought about it, tomorrow I'm going to pressurize the system again, and take off the oil fill cap and feel for air pressure.
 
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There was another guy here who fixed the huge blow by issue on his truck with a turbo swap.
according to will24 Cummins procedure dictates verifying the turbo is not an issue.
up until now I didn't believe it was possible..
but it apparently is, it seems that the vw doesn't have enough displacement to cause issue at idle
 
Its gotta be entering on the return side of the turbo if so. oil pressure is much higher than boost pressure. I can see it being possible tho.
 
12vriviera said:
There was another guy here who fixed the huge blow by issue on his truck with a turbo swap.
according to will24 Cummins procedure dictates verifying the turbo is not an issue.
up until now I didn't believe it was possible..
but it apparently is, it seems that the vw doesn't have enough displacement to cause issue at idle
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Do you know cummins procedure for this?

Extended Power said:
Blow by?
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I already checked that, it seems normal according to vw guys. I haven't done a compression test though.

Cozze44 said:
Maybe perceived as blow-by? But is actually air entering system through turbo?
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Thats what I was trying to imply in the original post. I was dog tired when typing it though lol

ComnRailPwr said:
Its gotta be entering on the return side of the turbo if so. oil pressure is much higher than boost pressure. I can see it being possible tho.
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That was my guess. And with the bilge pump pulling oil through the turbo, pressure can't build up at all to "keep the boost outside" where it belongs.


So I don't sound crazy with this idea?
 
madmikeismad said:
So I've been losing sleep at night trying to figure out why the vw won't spool the hx35. It will start to spool, and then just kinda fall flat and maintain that pressure. I pressurized the sytem to 30+ psi and couldn't find any leaks anywhere.

Then I started wondering what would cause the valve cover to literally BLOW oil all over the bottom of the hood, and why it only does it when driving. I can rev it up in neutral and it doesn't seep oil at all.

Then I remembered how the holset was leaking oil out of the exhaust and compressor side, and I fixed it with a bilge pump.
Click to expand...


Can you fill me in on how you fixed the oil leak exactly?


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mathews8pt said:
Can you fill me in on how you fixed the oil leak exactly?


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Click to expand...

A pump to pull the oil out of the turbo. It's not able to drain fast enough into a vw block in a vw car. Stock drain is too high, and drain welded into pan is below the oil level.
 
madmikeismad said:
A pump to pull the oil out of the turbo. It's not able to drain fast enough into a vw block in a vw car. Stock drain is too high, and drain welded into pan is below the oil level.
Click to expand...


Could that be inducing pressure into the case somehow?


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mathews8pt said:
Could that be inducing pressure into the case somehow?


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Click to expand...

Do you mean is the pump itself increasing case pressure? I don't think so. Especially since it's a constant pressure/flow pump, and extremely tiny, and it doesn't blow any oil at idle. The shop I got it from is running it in the same setup with a smaller turbo on their alcohol bike with no issues. Though he said on the bike it makes 160psi oil pressure into the oil return lol

I was also curious (extremely hypothetical) if it was possibly pulling so much suction that it could be pulling in the seals on the turbo, but I figured it would just pull air/oil from the oil supply first. I know it all sounds ridiculous, but we've all seen crazier stuff happen.
 
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Of all things I've heard this one is very very unusual, after reading everyone else's opinion I would lean towards the same thing. Oil cannot be removed from the turbo fast enough and is seeping through seals internally.

On a sidenote the thing with the bilge pump sounds crazy, how tiny of the bilge pump is tiny?


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Whats the best way to test for blowby from the compressor in the oil drain? Im guessing just pull the drain off the side of the block and have it drain into a bucket for a couple secs.
Would this even show at idle? The amount of blowby oil oozing out on the valve covers is just insane. I cant think of anything else that would do this besides constant air coming up through the tappet holes.
 
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Is there a pcv valve on the tappet cover? Is it plumbed up and functioning correctly?
 
kawi600 said:
Whats the best way to test for blowby from the compressor in the oil drain? Im guessing just pull the drain off the side of the block and have it drain into a bucket for a couple secs.
Would this even show at idle? The amount of blowby oil oozing out on the valve covers is just insane. I cant think of anything else that would do this besides constant air coming up through the tappet holes.
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Pull the turbo drain and feel for air when you pressurize the system, or pull the oil fill, dipstick, etc....

Str8jacket said:
Is there a pcv valve on the tappet cover? Is it plumbed up and functioning correctly?
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Its just a vent in the valve cover. Are you thinking of those imports that have boost leaks through the one way pcv's that fail?
 
Yeah thats it, often plumbed to the inlet tubing to the turbo, had one block the filter/seperator bit in the tapet cover and blowby would blow the dipstick out, fixed that and blew the rocker cover seal out, only when driving. Cleaned it all out all good.
 
Not knowing how these things are put together makes this harder. Im guessing there are two oil seals, one on each side of the center section?
Pressurizing the system on the intake side would be easy and tell me if a seal was bad on that side.. How would you test on the exhaust side for a leak? via the exhaust pipe and some sort of expandable insert with an air fitting on it?
This is assuming that both seals dont necessarily fail at the same time.
 
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If any cylinder has both valves even cracked open, it will pressurize the exhaust side too. I plug the intake and the exhaust when I test. And for my purposes, I don't care which seal is bad. If one is bad, the turbo has to come off anyways lol
 
how much oil does the turbo retain after its been shut down for awhile?
Might be easier to just seal the oil feed, pressurize the oil drain itself and listen for leaks.
 
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