HX40 is leaking again?!

[mini612]

I bought a used HX40 for my project and it keeps leaking externally, its leaking where the center housing meets the turbine housing (oil appears to be seeping through the piston ring). I replaced the journal bearings, snap rings, installed gapless piston rings, and all components that came with the kit. I followed the instructions and made sure everything was correctly assembled. This is the second time I rebuild this turbo because of this leak. The oil feed is 4AN (i used the vanos feed port) and the oil return is 1 inch, and I tapped the front engine cover for the return. My oil pressure appears normal, 40-45 when start and down to 20ish when op temp. I am beginning to think that I bought a bad turbo. If any one has any ideas/leads please let me know.

[Northern]

any chance the drain is kinked?
-16AN should be plenty unless it's kinked, clocked far from vertical, has some other sort of blockage, or there's a crankcase vent/blowby issue?

[mini612]

any chance the drain is kinked?
-16AN should be plenty unless it's kinked, clocked far from vertical, has some other sort of blockage, or there's a crankcase vent/blowby issue?

Thanks Northern for the response!!!! The oil return line can't really be kinked because I fab up an 1 inch ID steel tube (i thought what i had before was causing the leak so I decided to fab up something). I also checked for blockage before installing, and the center housing is vertical. I vented 2 spots to atmosphere; one from the original and the second, I made using an older oil cap, drilled a hole into it. Both goes to an oil catch can that is then vented atmosphere.

[mini612]

I read somewhere on the web that some people were running into the same issue, of course on different car models. So to resolve this, they used a 1.5mm restrictor. I think that 1.5 is pretty tiny for journal bearings! I am currently at 4an with no restrictor. This seems to be leaking at idle, so this means that the wheels/blades are not spinning fast enough and i might have too much oil going into the turbo. So, I just ordered a 1.8mm banjo restrictor to see if it will stop the leak. I'm unsure if this will oil starve the HX40. But because I ordered 2 different rebuild kits, I have extra journal bearings if restricting the oil in this turbo messed up the bearings.

[14thirty]

Is the drain 1 inch all the way through? Some of the adapters on the turbo end reduce the size quite a lot.

Would adding a pre turbo hose for the catch can help? Rather than vent to air.

Unrelated, but I think your air filter is too small.

[Northern]

When I ran an HX35/40, I had a restrictor.
Lots of people will point out that you shouldn't need a restrictor on a journal bearing turbo, but it does seem to be common on these turbos.
Worth a shot versus the alternative, and like you said, the bearings are cheap.

[tyeler18]

What's your highest oil pressure you're seeing? Your hot oil pressure is fine but holsets are very temperamental about oil pressures. 60-80psi on the top end is about where we start to see oil blow past the sealing rings on DSMs.

[mini612]

What's your highest oil pressure you're seeing? Your hot oil pressure is fine but holsets are very temperamental about oil pressures. 60-80psi on the top end is about where we start to see oil blow past the sealing rings on DSMs.

Thanks tyeler18 for you input, it's been a few months since i've been active on here. Yes, my turbo still leaks but since it's winter here in MN, my car is in storage until spring. Oil pressure at idle is about 15-20 psi. Ive read somewhere that if the turbo is not spinning enough, it'll leak? No leak on the cold side, and i don't think it's leaking internally on the hot side, BUT it's forsure slowly seeping through per the pics i posted above.

[mini612]

When I ran an HX35/40, I had a restrictor.
Lots of people will point out that you shouldn't need a restrictor on a journal bearing turbo, but it does seem to be common on these turbos.
Worth a shot versus the alternative, and like you said, the bearings are cheap.

Hey Northern, I am running a restrictor, it's 1.5mm, and yes it's still leaking!

[Northern]

Do you know when it is leaking (more noticeable after a bunch of WOT or time in boost?)

What ID are those lines to the catch can, and is it just vent to atmosphere through that filter or is there vacuum on it as well?
Just asking because they look small in the picture. Either the lines or that filter might not be able to flow enough to keep the pressure down at WOT

[mini612]

Do you know when it is leaking (more noticeable after a bunch of WOT or time in boost?)

What ID are those lines to the catch can, and is it just vent to atmosphere through that filter or is there vacuum on it as well?
Just asking because they look small in the picture. Either the lines or that filter might not be able to flow enough to keep the pressure down at WOT

It’s been a while since I’m in here. I think the ID of the breather tubes are 1/2”, I did have 1” ID tube on there before I switched to two 1/2”, and it was still slowly seeping. The leak usually occur when I’m at idle. At that time, no leaks at WOT. The leak is a slow leak. Not sure if this matters but I am using a m52b28 oil pump.