Broken breather thing

pol · Post by **pol** » Sun Feb 25, 2007 8:36 pm

Hi all,

I've been searching for vacuum leaks again and found that the valve thype thing inside a kind of foam cover that fits on an (oil?) breather is damaged and must be leaking for a start. I have bypassed it for now but need to replace it.

What does it do? How does it work? Seems like a rubbish design. Does anyone have a spare?

(this isnt my engine ay, mine has the silver manifold but the part looksthe same)

Also today I found part of my MBC had melted so had a big hole in it, probably causing a big leak too. It feels so slow now.... Errr Rich....??

I'm sure there's something wrong with the vacuum pressure although it shows -14 on the gauge. I'm trying to get a new atmospheric dump valve to work, I binned the last one I while ago as it had the same problem of not opening when in -pressure but this one does the same. I know they may not be a great idea, but the fact it doesn't open as it should suggests a problem. Any thoughts? It's annoying me!

Cheers,

pol

martinholmesuk · Post by **martinholmesuk** » Sun Feb 25, 2007 9:41 pm

Oil sep valve / vents back to inlet side.

it's around Â£45 from volvo and comes with the cover.

owen080808 · Post by **owen080808** » Sun Feb 25, 2007 9:57 pm

man those things are crap. i broke mine by something a little less vigorous than looking at it, managed to salvage it with some spare rubber pipe, but yes, they are rubbish, if you're getting one second hand take extreme care removing it, volvo brittle plastic at its best!

pol · Post by **pol** » Sun Feb 25, 2007 10:18 pm

Can it be bypassed properly? Any description of how it works or what it does? At the moment I have the pipe on the manifold bloced off and the other pipe connected to the top of te breather without the valve. Just been reading through other posts and i'm thinking i shouldnt do that or i'll be sucking oil / crappy vapour right by the turbo, or is that what happens anyway? I read something about reather filters.. Is that a crankcase breather?

Thanks,

pol

crispy-d · Post by **crispy-d** » Sun Feb 25, 2007 10:53 pm

I've no idea how the oil sep valve works, but I think the breather filter can just clamp on to the crankcase breather (the honeycomb thing (thanks for the spare, Martin!)) and then the two pipes that connect to the valve can just be blocked up - should stop rough running and idling. As long as it will pass the MOT like that I may just leave it like that as it seems to run much better.

VanDerGraaf · Post by **VanDerGraaf** » Sun Feb 25, 2007 10:57 pm

pol wrote:Can it be bypassed properly? Any description of how it works or what it does?

I too have never been clear on the function and purpose of this thing. Would also like to know more before I would be happy messing about with it.....

martinholmesuk · Post by **martinholmesuk** » Sun Feb 25, 2007 11:08 pm

If you block it from the block then pressue will build up.

If you remove the black can you can see to the bottom of the sump.

pol · Post by **pol** » Sun Feb 25, 2007 11:26 pm

Found some filtrs on the bay. think i'll give them a go.

There's another valve to the left of that one (not in that pic i dont think) that connects to my idle valve... What is that for too?! Too many brittle plastic valves around for my liking. I want air tight!

pol

crispy-d · Post by **crispy-d** » Mon Feb 26, 2007 2:45 am

I think that's contains the diaphram Martin mentioned in another post in regards to bad idling. Have no idea why it's there or what it does, but if it's split then that would explain why mine idles too high when warm (or too low when cold if I turn it down) as it leaks excess air through into the manifold. I miss my motorbike - was so much simpler!! None of these silly valves or fiddly electronics all over it!

Is it a sensor or just a heater that sits just before the turbo inlet on the oil breather return pipe? Only if it's a sensor and isn't getting a reading, as the pipe will be plugged, will it send a dodgy reading to the ECU, messing things up?

pol · Post by **pol** » Mon Feb 26, 2007 9:57 am

Not sure what it is either. All I know is its plugged in to something. It does seem like a fiddly system.

I can also hear a kind of shuddering noise of air escaping through the air filter when i let off the revs which i've heard someone say before but dont remember the problem. Doesn't seem right. Just trying to get my head around the air flow circuit and its valves and things...

pol

pol · Post by **pol** » Mon Feb 26, 2007 10:23 am

Just been reading old posts:

http://volvo480.northernscum.org.uk/for ... php?t=6446

Did you guys ever find / try using another non-return valve. I'd be interested in this. I don't really understand how the air / gas is supposed to flow. Theres the outlet from the oil sep, the inlet and the return to air in before turbo.

Thanks

crispy-d · Post by **crispy-d** » Mon Feb 26, 2007 11:40 am

The shuddering/fluttering sound you hear when you close the throttle will be a split diaphram in the recirc valve. Mine's doing the same at the moment - still need to get that 710N replacement!

pol · Post by **pol** » Mon Feb 26, 2007 2:50 pm

I dont have the re-circ attached, got a atmospheric one... I can't work out if my vacuum isn't strong enough or there is another problem? But if the atmospheric one doesn't work (which is airtight and rebuilt) then i just reckon something must be up, which has led me to the broken valve so far and i still suspect other bits...

pol

bbf · Post by **bbf** » Mon Feb 26, 2007 3:00 pm

Get that 710N for 25GBP and original oil breather valve, part# 3451221 for about 40â‚¬ and forget your troubles. 710N is uprated and used in WAG as exchange for old underrated, which was exactly the same as ours.
don't bother with alternatives, you'll waste your money. and don't bypass separation valve, it's there from a reason! it switches chrankcase ventilation between direct/intake manifold at underpressure and between
ventilation through turbo intake at boost and the same time closing direct connection. This is preventing boost entering the crankcase.

don't use atmosferic BOV, engine management isn't compatible with it.

the small 'sensor' before turbo intake is a heater which prevents ice formation in breather hose, so that the ice particles don't enter into the spinning turbo

more info: http://naveza.mine.nu/volvofiles/volvo3 ... system.pdf

pol · Post by **pol** » Mon Feb 26, 2007 3:17 pm

Cheers, but what is a 710N - I dont think this will help!

What is it and where can i get one?! Thanks.

pol

pol · Post by **pol** » Mon Feb 26, 2007 3:19 pm

710N = re-circ valve?

pol

crispy-d · Post by **crispy-d** » Mon Feb 26, 2007 6:20 pm

Thanks for that, bbf. Sorted that one out then! I've just bought a breather filter (for Â£5.99)

Should I take that back then? Is it not better to just vent the oil vapours to the atmosphere anyway and block the pipes up so there's no air leakage? Or is it actually bad?

Pol, the 710N is part of the part number for the recirc valves that go in the Audi TTs. I've forgotten the site, but it's on the forum somewhere. Just type in VAG parts and 1.8T dumpvalve! Should get there. I'm off to buy one now! It doesn't give you "an amazing colour calibration system" but should give "you perfect performance everytime."

bbf · Post by **bbf** » Mon Feb 26, 2007 7:54 pm

i don't know what you bought and i don't know if it's bad blocking and porting crankcase open-air. i did as it was originaly and i thrust it.
bdw, i got 710n from here:

http://www.thettshop.com/oem.asp?cat=2006&product=50000

good luck!

rpruen · Post by **rpruen** » Mon Feb 26, 2007 7:55 pm

pol wrote:Just been reading old posts:

http://volvo480.northernscum.org.uk/for ... ply&t=6446

Did you guys ever find / try using another non-return valve. I'd be interested in this. I don't really understand how the air / gas is supposed to flow. Theres the outlet from the oil sep, the inlet and the return to air in before turbo.

Thanks

The part that fails on the breather valve is the small non-return valve in the outlet to the manifold. They are very rubbish, just a squishy bit of orange rubber. The rubber snaps off after a while, and gets sucked into the engine.

What happens is the non-return valve fails, and when the manifold is under pressure (boost) it pressurises the crankcase. That makes the seals and oil filler cap leak (or should that be leak MORE).

Just fit a small non return valve in the pipe to the manifold, so that the manifold can suck from the seperator, but not blow into it. The small line is there to draw clean air through the valve (from the turbo inlet, to the manifold when it's under vaccum) to purge the system, that way a flammable vapor won't build up. Also for emmisions the engine burns any fuel / oil vapor.

I have a bigger seperator valve, but the standard system for crank case venting. I don't have the valve at all, but a non-return valve screwed into the manifold. It all seems to work ok, apart from a slight noise from the non-return valve (though the supercharger drowns that out quite nicely, may be an issue if you don't have a supercharger).

Richard

pol · Post by **pol** » Mon Feb 26, 2007 10:02 pm

Thanks rpruen... So when under vacuum, the valve allows flow into the manifold from both the oil sep and by the turbo inlet at the sme time / mix? And under boost does not flow in the other direction back to the oil sep and the inlet?

So I could make something with 2 separator valves and a 'T' piece that would do the same job but be stronger? So if both the Oil separator and feed from turbo inlet both had valves and both connected to the manifold I could avoid using the tacky plastic bits and keep the original designed flow?

Or maybe i can find a 3 way or 2 in to 1 seperator valve somewhere?

pol