TDI engine breather...

'evening all,
I thought that i would post the details of an engine breather that i have been running on my A2 for around 6 months, as i haven't found a similar post where anyone else has done this.

This mod was first carried out on my 2.5 TDI allroad, after i discovered oil throughout the entire induction system and the mess that it makes of the turbo and manifolds etc.

All i did, was to remove the crankcase breather tube from the turbo inlet, plug the hole and make a filter casing and element so that the crankcase vents to the atmosphere, rather like engines of old.

The filter can be changed and the engine spared of having to burn the oil vapor and condensation that the breather emits.

The result on the allroad was dramatic; the turbo and pipework stayed clean and exhaust emissions were reduced.

When i bought the A2 and took the induction trunking, egr valve etc., apart, the same problem was evident and so i made up a similar filter.

I removed the link pipe from the rocker cover to fit the filter trunking and blanked the union on the inlet next to the turbo.

The filter canister was made from an empty aluminium cosmetic container and the filter medium is a rolled up kitchen scourer.

A sleeve inside the cut-off end of the canister allows removal and refitted for servicing.

The pipework is made from bits laying around in my garage.

I think i bought 2 jubilee clips, but that's all.

The A2 was MOT'd last week and there was no visible exhaust emissions, whereas i had previously seen some in the mirror under hard acceleration, so i think that my cheap and minor mod has been successful. The tester was impressed too.

When i checked the filter there was oil present after a couple of thousand miles and in the winter, a lot of condensation had collected too, all of which is better out than in, in my opinion...

G.

excellent idea, will be making myself one of those over the weekend
Thanks for the idea

Yes, with 284k on the clock, i expect you're in the same boat.

Mine has only done 120k miles.

My next job is to clean up the turbo and manifold.

G.

I would advise reconnecting original pipework !!!!

I like the idea of an oil catcher as such but your plan is flawed i beleave ...

The way i see it the breather is needed to releave compression from the sump , my theory being you get the same compression both sides of the piston rings , one being compressed with fuel and air for a bang and the other fills the sump area , hence the breather to remove this, the breathers designed in such a way that it does not pick up oil , just vents the engine, my thinking of removing this is only going to have an adverse affect and advise to put things back to original

Note : the gunge you find in the inlet side of things is a mixture of all the soot and carbon from the EGR valve, having this blanked off is a wise thing to do although engine warm up times increase slightly,,, oil vapour is minimal from the vent and not a bad thing its the soot and carbon deposits that make all the mess, if you have excessive oil in the bottom of the oil cooler hoses id be more looking towards turbo seal s

Thanks for the response, it's always good to get feedback.
My filter still relieves pressure in the sump, but.does not allow the oil vapour or condensation to be recirculated.
The link pipe from the rocker cover originally directs all of this straight back to the turbo and eventually the egr valve, so removal must surely clean up the air that the engine breathes and therefore the exhaust gasses too..
I have removed and checked the induction trunking several times since I fitted this and no oil was present.
When I rebuild the turbo I'll check the seals though.

I think the actual fix is to replace the PCV valve, contamination of inlet components is normally through a blocked / faulty pcv valve which is forcing blow-by from the engine into the inlet manifold.

Without the PCV system in place and positive airflow through the crankcase, blow-by will contaminate the oil much quicker that without with water vapour and light hydrocarbons. Not to mention emissions... (not through the exhaust, but through the breather)

If your set on keeping the breather I would consider much more frequent oil changes.

Nick

Any update on this TDI inlet breather mod and turbo inspection from last year ?

Yep, it's still on the car and my intercooler pipework and egr valve etc are virtually oil free.
The car has now covered 134k and goes well, with no exhaust smoke.
I clean the breather filter housing and change the filter once or twice a year and that's it.

I thought the oil in my inter-cooler etc was unavoidable as it originated from the turbo seals? Perhaps not?

Is there an environmental impact with this arrangement? I thought the purpose of the breather was to take nasty gasses from the crankcase, burn them in the cylinders and burn the resulting combustion byproducts again in the soot burner? Venting to your engine bay is the same as venting direct to atmosphere?

Apart from that concern looks like a good idea to me. Perhaps fit an oil trap and still burn the gasses; something like the components in a compressed air line?

philward said:

I thought the oil in my inter-cooler etc was unavoidable as it originated from the turbo seals? Perhaps not?

Click to expand...

There's no such thing as a seal in a turbo. The operating temperature and speed of rotation mean that any conventional seal would have a very short life. The "seals" such as they are, are two oil flingers which keep oil away from the shaft using centrifugal force.

RAB

Thanks for the clarification @RAB .

Can the oil weep out when the turbo is stationary / shutting down and the oil fingers are ineffective / less effective?

Would it be an idea to fit a oil catch tank to this breather arrangement,they have a inlet as well as a outlet to let clean gasses still to pass though but catch any oil and sludge.Just empty the catch tank on every service

pete

P stamp said:

Would it be an idea to fit a oil catch tank to this breather arrangement,they have a inlet as well as a outlet to let clean gasses still to pass though but catch any oil and sludge.Just empty the catch tank on every service

pete

Click to expand...

I had considered this, but hadn't found a suitable container, but to be honest, most of the oil is absorbed by the filter element ( a scotchbtite).

There is only a very small amount of residual liquid in the filter housing.

Depending on mileage and therefore how heavily the engine ' breathes ', it may only needs a wipe every now and then and a filter change.

The frequency might increase with mileage.

If a more absorbent filter can be sourced, it might work better, but tbh, it's worked fine for me so far.

I only made this out of bits and pieces that I had in my garage, based on my experience of all sorts of car and bike engines, but I'm not an engineer,.

If someone wants to develop it further, please feel free to do so and share.


Cheers

G.

philward said:

Thanks for the clarification @RAB .

Can the oil weep out when the turbo is stationary / shutting down and the oil fingers are ineffective / less effective?

Click to expand...

Yes, the flingers wouldn't be very effective when the turbo is stationary. I have just stripped down and cleaned the VNT mechanism on my wife's 3L. On the piping piece that connects the turbo inlet to the intercooler and the breather to inlet, there was no trace of oil on the inlet from the intercooler; not bad for 20-year old turbo. There however, a little oil in outlet of the intercooler.

RAB