One for the TDi gurus

[klappers]

Just trying to find an oil leak and started to play around with the breathers on the TDi.. So my question is, what does the front breather on a TDi do and where does it breathe from?? By front I mean the one the is at the front of the motor as you face it? This seems the be the only thing that "breathes". Took off the factory oil air separator and it seems to be clogged because when I put it on there is no breathing out of the top line that goes back to the turbo..

Cheers

The Klap

[roverrescue]

By 'front' do you mean the hose that links from the rocker cover down to the lower block?

As far as I am aware that simply equalises pressure between top and bottom end.

The cyclone seperator takes blow by gas (seperates oil to the sump) and returns it to intake.

If you have no excess pressure coming out the rocker cover through the cyclone outlet it simply means you have limited blow by / good sealing in the pots. On the other hand my old, dusted worn out 300 chugs like a freight train out that breather and drinks engine oil like an old laser!

S

[klappers]

There is pressure coming out of the one that comes up from the lower part of the block but there is no pressure coming out of the hose that goes striaght to the sump from the cyclone...

With the cyclone remvomed there is a little bit of pressure coming out of the rocker cover (this I later found out to be only from the front hose and nothing else) but when I re attach the cyclone there is almost nothing coming out of the front hose on the cylone (this is the outlet that goes to the turbo inlet), which makes me wonder how this works etc and is it possible for this to be blocked

[klappers]

https://www.aulro.com/afvb/images/imported/2011/03/949.jpg

This shows what I am talking about... The hose infront of the oil air separator seems to be the only thing that really has any pressure...

[roverrescue]

The cyclone isnt really that complicated.
Spins the air, heavy stuff drops out the bottom pipe to sump, side outlet goes to intake.
I would imagine at idel the 'system' probably isnt working as it would normally.

More imprtantly - whats the oil leak your chasing!

S

[klappers]

well oil is coming out from somewhere here.. so need to find out what it is and stop it
Its not head gasket or anything like that. The oil sits just below the cyclone on the lip near the injector... So, just wondering if you could possibly block a cyclone which would cause issues.

[roverrescue]

I guess anything is possible! Maybe a blocked cyclone.

The hose you mention is for equalisation of pressure between bottom and top... by their nature diesos will get top end blow by hence the need for rocker cover scavenging. The cyclone simply separates oil from the blowby and returns it to intake.

If you pull the cyclone and put pressure into the 'intake' what happens?
Now block the line to the sump and add pressure - what happens?


Pull and test would be a start I guess? Or Provent it!

S

[rrturboD]

The separator has an o ring, around the body that bolts into the rocker cover. Is the oil coming out of this junction, running down head? If so, replace o ring, or as a lot do, add a little silicon to the o ring and re bolt in.

[klappers]

I guess anything is possible! Maybe a blocked cyclone.

The hose you mention is for equalisation of pressure between bottom and top... by their nature diesos will get top end blow by hence the need for rocker cover scavenging. The cyclone simply separates oil from the blowby and returns it to intake.

If you pull the cyclone and put pressure into the 'intake' what happens?
Now block the line to the sump and add pressure - what happens?


Pull and test would be a start I guess? Or Provent it!

S


Well there is a little bit of suction on the inlet...

And with the sump off the cyclone when you block that hose nothing happens.. There is no pressure from the sump just the front hose

[Tiny Tim]

Hi all.
On a similar vein as the last chat, I've just bought a 300tdi with 400km and recent multiple engine oil leaks through, I believe, excessive crankcase pressure. It'd not leaking at present but being unregistered I can't really give it a workout. Should there be a negative pressure at the hose to the turbo when disconnected from the oil separator or is it neutral and allowing of any excess pressure from the crankcase. Would we need a few revs to show this condition up? Would gummed up exhaust baffles cause a back pressure thereby preventing scavenging of the crankcase? I'm planning to test the pressure with and without the muffler connected. Any comments welcomed.

[slug_burner]

Hi all.
On a similar vein as the last chat, I've just bought a 300tdi with 400km and recent multiple engine oil leaks through, I believe, excessive crankcase pressure. It'd not leaking at present but being unregistered I can't really give it a workout. Should there be a negative pressure at the hose to the turbo when disconnected from the oil separator or is it neutral and allowing of any excess pressure from the crankcase. Would we need a few revs to show this condition up? Would gummed up exhaust baffles cause a back pressure thereby preventing scavenging of the crankcase? I'm planning to test the pressure with and without the muffler connected. Any comments welcomed.

Should there be a negative pressure at the hose to the turbo when disconnected from the oil separator?

Yes