Breather Pipe?

[aragorn]

Ive been getting oily smell in the cabin since i baught the car 6 months ago.

I tried a few of the common fixes (rocker cover gasket was leaking and the dipstick tube was cracked) but the problem persists.

Today i was topping up the oil and while having a general look over the engine bay i noticed a pipe under the inlet manifold seemed to be wet with oil. At first i presumed it was just a rubber hose thats perished away as they often do when exposed to oil, however on closer inspection it seems that its either snapped at a fitting, or simply come detached...

i took some images:

looking down thru the inlet runners beside the dipstick you can see the pipe start:

It seems to come off the block at an angle, turn sharply back towards the block then turn sharply again and run along its length until this fitting:

Which you can see has a gap between it and the rest of the pipe. It seems to then feed into a much smaller pipe that runs upto the inlet manifold.

Is this just the crankcase breather and does it just connect to the inlet manifold?

if so, why hasnt the car experienced any running issues as i would expect that pipe will be allowing unmetered air into the inlet tract, (or letting boost out...)

Any gen?

 

[AUDI TURBO]

by the looks of it, it is your oil breather pipe. mine split a month back but i think it had bin split for ages. As you said it is there as a breather for the oil so if split etc you may get a slight smell around the engine when running etc. i did when mine was running you could see the pipe fluttering. new pipe was about £25.00 from local continental shop

 

[AUDI TURBO]

and mine had no running issues it was mot that found it? but not sumthing you want to leave as you aware it is leaking oil.........

 

[Lee Goodall]

Had exactly the same problem.. replaced with Audi part £30.00 ish I think and they had it in stock. Easy fix.

 

[aragorn]

looking at it i think there is a 1 way valve in the T piece that breather hose connects to which i presume is there to stop the boost pressure reaching the crank case. Which i presume is why its not leaking boost.

I would imagine however that the engine is leaking air in there while not on boost which will screw up the fuel map?

Some air will bypass the airflow meter at idle and low throttle angles, the ECU will detect this as a lean condition and adjust the fuel compensation values in its map to get the mixture correct. The issue then however is that when the engine comes on boost, those enrichment values will still be applied, but the one way valve will have closed stopping the air leak.

I wonder if my fuel economy will improve after its repaired as a result?

 

[aragorn]

Just phoned the local audi dealer with the part number from vagcat. They want £19.95+vat for the pipe and have it in stock so i reserved it. Will try to get over at some point and pick it up!

 

[mwarrey]

Hi, whats the part no. mine looks a bit ropey as well

 

[Lee Goodall]

Yeah apparently it's a common problem.. hence Audi always having the part in stock!

 

[aragorn]

http://www.vagcat.com/epc/cat/au/A4/1996/156/49/1741388/

the part number for the pipe is 058103213