Turbo leak vs Rings/Piston leak

Hello it's me again

1995 TDI 300 Auto no EDC no EGR


So I had a smoke problem that got worse then turned into a huge oil leak coming from the exhaust-spring portion (there's a hole in it) right under the turbo/manifold area. I finally got around to taking it apart and on removing the Turbo, hoses and manifold I discovered that the Turbo bearing is worn and it has been leaking oil. I also noticed that the cylinder head ports that the manifold fits onto is dry on the first, fourth,fifth and eighth holes and dripping oil on the the rest.
As I understand it, the the valves are Exhaust, intake - intake, Exhaust, Exhaust, intake -intake - exhaust. In other words the dry ports are the exhaust and oily ones are all intake. Based on that and the condition of the Turbo can I rule out that the oil was coming from a worn ring or piston and in fact was coming from Turbo. Also it was a LOT of oil literal dripping from the bottom, had there been that much oil coming from the engine wouldn't it have burned up most of it?

Thanks a lot.

Does anyone know where I can find core assembly for TDI 300 Turbo? I have been looking all day and can't find any in UK!

You might want to start looking at the valve stem oil seals that can allow oil to drop into the inlets, also turbo seals would allow oil to be blown through the intercooler,inlet manifold and inti the inlet ports. There are rebuild kits on ebay for the garrat t25 turbo think they are around the £46 mark

alex8882 said:

You might want to start looking at the valve stem oil seals that can allow oil to drop into the inlets, also turbo seals would allow oil to be blown through the intercooler,inlet manifold and inti the inlet ports. There are rebuild kits on ebay for the garrat t25 turbo think they are around the £46 mark

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Hi Alex,

I got a new Garrett core to be on the safe side. I also took the time to remove and clean all the hoses and intercooler. It worked well for a couple of days and about 200 kilometer then it suddenly started smoking like crazy. Clouds of smoke.
I pulled over immediately and popped the hood open. There was whistle coming out of the oil cap (some sort of pressure built up in there) and oil dripping around the turbo. I turned the ignition off and got it transported to a mechanic. He ran the car and with the outlet hose removed off the Turbo. Oil was coming out of there and he concluded it was a bad turbo. I mentioned the stem seals and he rejected that idea and commented that it would go into the engine rather than out of the manifold intake.

Can you please expound on your suggestion that it may be the stem seals?
What was the cause of the whistle and pressure building inside the oil cap?

I was thinking about this again.

Let's say the stem seals are bad and somehow that leaks oil to the manifold which explains the oil in the inlet ports. When I ran the car with outlet pipe that goes from turbo to intercooler off, the smoke stopped and oil dripped out of the turbo. How does the oil going past the stem seals get to the turbo?

Someone on another forum suggested worn rings. How does the oil going past the rings end up at the turbo? And wouldn't it smoke regardless of the hose being removed off the turbo if the rings were worn and oil was being burned in combustion?

I took the new turbo back to the Garrett dealer for testing and they said it was working well and it did not leak.
They suggested the return hose which I checked and had just replaced (used one) with the turbo.
The also suggested that there could be back pressure due to a plugged breather (Cyclone).
So I took the turbo back to the mechanic who checked the cyclone and found it OK (just removed the hose and felt the air coming out with the engine running). So he now thinks and will check some sort of a "return valve" or port of some sort somewhere close to where the oil filer is and he said that if it is plugged and the oil in not free to return it could cause a pressure build up which impedes the oil return from the turbo. What exactly is this valve, I have yet to research.

And as I wrote above, when the car smoked and I opened the hood while the engine was running there was a whistle coming from the oil cap and when I turned the engine off it continued for a little bit indicating there was pressure built up at least inside the crank case.Can the cyclone plug itself or malfunction on and off? Can whatever valve he's talking about cause that pressure build up at the crank case?