1.9 TDI Breather Disconnect

[mrcheeezy]

I have a 1.9 TDI 2003 A6 with a 130 PD AVF engine that has done 130k. The engine seems fine pulls well no real oil burn but does seem to blow a lot of oil via the breather into the induction system.

Some Questions -

Can I disconnect the breather from the top of the rocker cover and vent to atmosphere? does the engine need this oil spray from the breather to lube the engine top end or turbo?

Is there another breather that might be blocked - other than the rocker cover - that might be causing excessive crankcase pressure?

[Crasher]

They do breathe oil, just leave it as it is. It is illegal to vent crankcase fumes to atmosphere.

[mrcheeezy]

Ok I understand, but I just want to diagnose a poss oil issue here. It cant be that good for the environment to be burning excess oil? Could it be the oil seal on the Turbo? is it worth putting a oil catcher can in the breather pipe work?

[Crasher]

They do blow oil into the inlet tract, both from the turbo and the can cover breather. I have seen one year old VAG product with the PD engine with oil dripping from every coupling on the boost system. Unless the oil consumption gets out of hand (say in excess of 1 litre per 1K miles) I would not worry. The oil leaks from the connections so much on the Fabia VRS (130PD), that Skoda has made a hole in the lower cover at the input to the intercooler so that the oil can drip onto the floor, rather than pool on the lower cover. VAG have introduced thicker “O” rings for the couplings to try and stop the oil showing as they don’t consider it a problem.

[mrcheeezy]

Ok just out of curiosity I disconnected the breather and there is now no smoke from the exhaust - even under heavy accel. Interestingly there is not excessive gas from the breather and no oil being sprayed out.

Where could the oil in the induction system be coming from - the turbo oil seal? Its done 130k, is it worth stripping the turbo for a clean and perhaps bearing/seal replacement? What’s the easiest way to tell if it’s on the way out?

MPG has dropped off recently, performance still seems good.

[Crasher]

If you disconnected the cam cover breather, did you block off the pipe you disconcerted? Obviously you let the cam cover breath to atmosphere.

[mrcheeezy]

Yep I blocked off the pipe that went to the induction system - I didn’t want any dirt etc going that way. The rocker cover outlet I connected a long clear pipe that went to the bottom and rear of the engine bay to keep any gasses out of harms way - this vented to atmosphere.

As it was clear I could also tell how much if any oil was being sprayed out - none as it turned out.

I have read that the breather pressure can cause oil to leak from the turbo seal if its slightly worn etc?

[Peter D]

I suspect you have a blocked breather/flame guard and engine is pressurising and defeating the scavenge nature of the return oil feed from the turbo to the pressure in the turbo bearing is causing oil to seep into the air duct. I dealt with this in a recent thread on hear and replacing the brether unit completely cured the oil burn and apparantly the previuos owner had chenge the turbo trying to stop the burn then sold it cheap to get rid of it. Regards Peter

[mrcheeezy]

Thanks Peter, yes I saw your posts on the topic which started me thinking. I intend to take the large pipe that goes from the air filter to the turbo off and clean the flame guard you mention - is it in this pipe?

The breather from the cam cover seems fine. I dont think there is another breather that could be blocked? Sorry just a bit confused, the tech data prog I have dont help. I guess I need to take of the big pipe and have a look.

[Peter D]

As you sure the breather pipe is not bunged up. You dissconnected it and it did not blow or spray oil so there is no airflow It you open the oil filler does it pop the cap off i.e. sump pressure. Regards Peter