Turbo Oil Leak and the Debate on Crankcase Pressure

[CaptBeardilocks]

So I have an oil leak at my turbo outlet. GTurbo Green Wheel with about 35k miles on it in the last 3 years. Engine is a 1HDT running PDI intercooler. I also run a Mighty Mouse catch can.

If my memory is correct, the leak started as oil weeping out of the silicone outlet hose and then dripped onto the turbo housing. I could be wrong about that, but that's my memory: a sticky, oily outlet pipe. At some point it intensified and I was noticing oil on the frame and traced it up from there. There is very little to no oil in the airbox, so it's not the CCV pushing oil in (that's the whole point of the catch-can after all).

I emailed GTurbo about it and their response was:
"If the oil isn’t coming from the crankcase ventilation then there must be oil being pushed past the collar seal in the bearing housing. Catch cans are notorious for causing excessive crank case pressure and cause oil to be pushed past seals on the motor. i would suggest cleaning the turbo, changing the silicone piece and the clamps, then disconnecting the catch can and plumb it to factory location or to atmosphere. Test this out and see if it resolves the issue, this has been the cause for hundreds of leaking turbos that i have seen, so it’s a good spot to start."

My catch can has a flap (which I will be testing this afternoon) that is supposed to vent pressure through a filter to atmosphere but allow vacuum in the intake to the crankcase. I will post pictures of my catch-can set-up this afternoon as well in case anyone thinks it's too high or there are other flaws in my design/routing.

I have literally ZERO other oil leaks on the motor. Not the VCG or anywhere else. Everything was resealed 3 years ago and has performed flawlessly.

Assuming that the catch-can/venting set-up doesn't have any flaws, how would I be pushing this much oil through the turbo outlet? Is it possible that something failed internal on the turbo?

Is it possible that my oil pressure is too high the engine? Seems silly, but I'm at a bit of a loss here.

EDIT: I suppose I could install a manometer just to see what crankcase pressure actually IS. But what other factors could be involved here?

 

[CaptBeardilocks]

As expected, my catch-can easily allows even low pressure air from the crankcase side through to vent to atmosphere. So I have very high doubts that high crankcase pressure is to blame for this oil leak.

If memory serves, the silicon outflow hose was tacky with oil just a couple months into running this set-up.

Anyone have any guess on what might be the cause of this particular misery? I'd hate to think that the Grunter is toast after only 35k miles. GTurbo is slow to respond to any inquires so far....

 

[mudgudgeon]

Clean it all up, including remove intake hoses and clean them so there's no residual oil and vent the catch can to atmosphere, at least long enough to see if it's your problem.

If you have vacuum pulling air through the catch can into the intake, you have oil vapour coming along for the ride

 

[CaptBeardilocks]

I'm 90% sure it's internal to the turbo. There's no oil residue in the piping from the airbox to the turbo. Just in the turbo outflow pipe. And with the catch-can venting to atmosphere under crankcase pressure I don't think it's positive pressure pushing oil through the seal.

I still need to check the in/out play on the turbo shaft, which should tell me something about the seal health.

I also need to block off the catch can and double check that I don't have massive blow-by, but I don't think that is the case. I'll do those today.

I already cleaned the turbo/outflow pipe, the issue is that she's in the shop for a refresh and a transmission leak so driving it a bunch is not really feasible.

 

[mudgudgeon]

If you completely block the catch can, you're forcing pressure in the crank case to be released somewhere else.
Like, pushing past rings, or valve seals, rear main etc.

The photo you posted, oil looks to be coming from the compressor outlet hose junction, and running down the compressor housing.
If there's a small amount of oil vapour from the PCV, the compressor can sling this out of suspension, coating the compressor housing.

Route the catch can PCV hose in to a clear bottle vented to atmosphere, see if you get oil coating it?

 

[CaptBeardilocks]

I only meant to block off the catch can completely for a filler cap test at idle. To see what my blow-by is like. I wouldn't run the truck like that.

After these other tests, I'll take a run in it with the crankcase venting to atmosphere. I've never gotten more oil than a couple of ounces per 5000mi in the catch can. and I almost never have to add any oil btw oil changes.

The oil is definitely blowing out the outlet on the turbo. It actually bleeds out that silicone hose section, making the whole thing sticky/oily. It lessens as you go down the IC piping, but I still need to pull the IC and drain/clean it just to be safe.

 

[mudgudgeon]

only meant to block off the catch can completely for a filler cap test at idle. To see what my blow-by is like. I wouldn't run the truck like that.

IMO you'd be creating an artificial condition.

Blow by is what it is with an open PCV

The oil is definitely blowing out the outlet on the turbo. It actually bleeds out that silicone section, making the whole thing sticky/oily. It lessens as you go down the IC piping, but I still need to pull the IC and drain/clean it just to be safe.

My hdj81 had oily intake tubes when I got it. It was dripping oil to the point I thought it had a turbo issue.
I cleaned all the piping with solvent based degreaser, cleaned the turbo housing and put it all back together.
Clean rubber, clamped on clean alloy sealed it all up. Oily rubber will never fully seal with a clamp IME.

Small amounts of oil was still getting into the intake from the PCV, just not leaking out of the intake.

If it wasn't leaking at the intake hose junction, would you have any other indication there was oil inside the intake hose?
In my case, I really don't think it was anything to worry about, despite there being an oily mess until it was cleaned up and hoses resealed.

Not saying don't look into it, more that sometimes we try to solve problems that don't exist

 

[CaptBeardilocks]

My plan was to block off the PCV and pop the oil fill cap and see how much it danced. Just to see if I had excessive blow-by.

Having now taken the air filter to turbo intake piping off, there is a bit more oil down at the bottom/turbo mouth.

I'm going to clean everything up & see where I end up with oil after a test run.

 

[bj70bc]

do they recommend a oil restrictor for that turbo in the oil feed line?

 

[bj70bc]

some oil feed lines already have them at the fitting, mine did

 

[CaptBeardilocks]

do they recommend a oil restrictor for that turbo in the oil feed line?

One wasn't mentioned in the install paperwork. And they didn't suggest one in my brief exchange with their customer service.

 

[bj70bc]

i have a different engine and turbo so I dont know the peculiarities of your setup but i believe this is the reason for oil restrictors, oil pressure pushing past the turbo seals, you could try one as part of the diagnosis procedure, maybe after trying a few other things mentioned above

 

[KiwiDingo]

The Toyota oil feed / oil return flange already has a restriction on the oil feed with the diameter of the feed pipe they use.

 

[Dougal]

How many km on your engine and what are the compression numbers like?

Turbo oil leaks are always crank case pressure too high. But that pic doesn't look too bad. How long has it been fitted? Is the silicone boot leaking and just taking oil mist with it?

 

[CaptBeardilocks]

375k km. Just ran compression numbers and they're great (~480 average).

As far as I can tell, there was some oil mist coming from or through the turbo (still TBD on that) and it leached through the silicone hose until it was running down the turbo housing.

I've currently cleaned everything & and am letting the catch can vent to air. I only managed about 25 miles on that test set-up before I had to crack into some other minor issues that need attention/general maintenance, so she'll be sitting for a bit.

For this test set-up I was venting the catch can into a plastic bottle (with vent holes) and got zero oil residue into it at all. So blow-by can't be that bad. No oil in the turbo charge outlet after such a short distance either. Will have to run it more and check again once the rest of the truck is put back together.

 

[Dougal]

375k km. Just ran compression numbers and they're great (~480 average).

As far as I can tell, there was some oil mist coming from or through the turbo (still TBD on that) and it leached through the silicone hose until it was running down the turbo housing.

I've currently cleaned everything & and am letting the catch can vent to air. I only managed about 25 miles on that test set-up before I had to crack into some other minor issues that need attention/general maintenance, so she'll be sitting for a bit.

For this test set-up I was venting the catch can into a plastic bottle (with vent holes) and got zero oil residue into it at all. So blow-by can't be that bad. No oil in the turbo charge outlet after such a short distance either. Will have to run it more and check again once the rest of the truck is put back together.

Catchcan removed and breather plumbed to intake will flow much better than catch can vented to atmosphere or into a bottle.

The biggest blow-by flow occurs at max load and is hard to test.

 

[CaptBeardilocks]

Catchcan removed and breather plumbed to intake will flow much better than catch can vented to atmosphere or into a bottle.

The biggest blow-by flow occurs at max load and is hard to test.

“Breather plumbed to intake” as in stock configuration?

There seems to be some confusion on the effectiveness of catch cans on these motors. I certainly wish there was some real science to dig into. Lol.

 

[Dougal]

“Breather plumbed to intake” as in stock configuration?

There seems to be some confusion on the effectiveness of catch cans on these motors. I certainly wish there was some real science to dig into. Lol.

The real engineering was done by Toyota and they say it doesn't need one.

 

[CaptBeardilocks]

They also designed it for a lot less boost than I'm running.

 

[mudgudgeon]

The real engineering was done by Toyota and they say it doesn't need one.

Their system leaves a very dirty oily mess in the intake downstream of the PCV hose.

Plenty of chatter and pics on the Web of intakes badly cakeed up with oil