likelihood of blocked turbo oil drain pipe
 

Has this ever happened to anyone?

I'm trying to troubleshoot a big oil leak around my turbo area and so far I've replaced the turbo with two different rebuilt turbos and replaced the oil line gaskets several times.

There's only two other possible culprits I've narrowed it down to and that is that either the oil drain pipe connecting to the turbo has some sort of blockage or that the rebuilt turbos I have require an oil line restrictor (this would be the case if the stock restrictor cartridge was removed from them when they got rebuilt).

I'm thinking that a blockage in the drain pipe would be very unlikely since the thickness of that pipe is somewhat greater than the oil feed pipe and for something to get through the feed pipe and than get stuck in the drain pipe would be impossible. The only way a blockage could happen in the drain pipe is if something broke off of the turbo since it's positioned after the oil feed pipe.

Never heard of that. But best bet would be to take the drain pipe off to ensure it is not plugged with something. The feed line should be 1/4 inch or close to that and the drain should be about 3/4 inch. Just telling you incase you are not running original lines.

if you are leaking oil, try using one of those oil leak dye tester. With ultraviolet light, it will pinpoint the leak for you.

I got under the car while it was running to see that its coming from either the chra, or the inlet to the drain pipe. But the drain pipe is as sealed up as it can be, and so any leakage from there either means that there's too much oil pressure at the turbo, or drainage isn't adequate.

It's just a matter of determining which of those it is. The leak is very big and I lose 1 litre in about 5 minutes. Is a leakage like this generally what happens when you don't have an oil restrictor and there's too much pressure, or does it seem more likely that it would be a blockage?

I dont have a oil restrictor in a hybrid turbo I had before and I have never leaked any oil in the amount you have. Even at 70psi of oil pressure.

You will need a huge blockage to block the oil return. Like, something coming off inside the turbo and blocking the drain. The oil drain inside the turbo is huge, its atleast 2 cubic inch.

It can also be a blown oil ring seal on the compressor side. There is a rubber seal that seals the oil lubricating the thrust bearing, if that seal is blown, it will leak oil from between the CHRA and the compressor backing plate.

Are you burning oil from the exhaust when it is running? If not, you can rule out the piston ring on the turbine shaft, and its leaking from the compressor side.


edit : woops, forgot you went through multiple turbos and still had the problem, ignore my post then LOL

or your pipe flanges are bent.

I am tempted to think you have a leak on the turbo oil inlet pipe/flange and not the drain side.

1l in 5 minutes is a lot of oil- even if the drain had a leak it is larger diameter and the oil pressure is lower so I would think it would drip a bit of oil but most would flow down the drain.


The factory turbo oil inlet lines crack where the pipe meets the flange on the turbo from thermal expansion- had it happen twice.

Make sure you use the factory gasket as it is asbestos and insulates the flange/pipe from thermal transfer off of the hot turbo.

Hope you find the leak.