Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: Debs. on 02 March 2008, 13:48:17
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Plucked-up courage to tackle a breather-bridge clean; they were indeed very 'cruddy' and near to being blocked.
There was also significant crud lying down-low in the throttle body butterflies: all parts have been cleaned/flushed out.
Most all of the job went well except for the large (kind-of caged?) o-ring underneath where the bridge sits down into the plenum/manifold.....anyway, that o-ring was toast and fell to pcs as I lifted the breather-bridge up.
I had a 'plain' o-ring in stock that`s a perfect tight-fit and have used that: would there be consequences for not using the original 'caged' type o-ring? :-/
Actually, the old large o-ring must`ve been toast for a long time as the engine is much quieter now and the 'hissing' which characterised the (bonnet-up) idle previously has now gone. :y
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Plucked-up courage to tackle a breather-bridge clean; they were indeed very 'cruddy' and near to being blocked.
There was also significant crud lying down-low in the throttle body butterflies: all parts have been cleaned/flushed out.
Most all of the job went well except for the large (kind-of caged?) o-ring underneath where the bridge sits down into the plenum/manifold.....anyway, that o-ring was toast and fell to pcs as I lifted the breather-bridge up.
I had a 'plain' o-ring in stock that`s a perfect tight-fit and have used that: would there be consequences for not using the original 'caged' type o-ring? :-/
Actually, the old large o-ring must`ve been toast for a long time as the engine is much quieter now and the 'hissing' which characterised the (bonnet-up) idle previously has now gone. :y
Only about £1.20 iirc, so may as well fit proper one...
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If the O ring is a good fit then you should be OK as far as air leaks are concerned but you will have upset the multi-ram working because part of the fancy seal is there to keep the left and right intakes separated.
If you get a new seal, dont forget to unbolt the throttle body before trying to remove the breather assy. You might also need the O rings for the two breather pipes- throttle body, they only seem to survive removal once or twice.
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Is this just on 2.0 or the v6 too?? I have the hissing noise under plenum with bonnet up and the car runs really rough...its an air leak I'm sure but need to work out where and how to fix it...
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mine's making the same hissing noise, i got told about it being the o-ring for the breather brdge.
it runs ok must be a common problem.
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Well mines running like crap, idling rough, struggling to accelerate (although this varies and is fine at higher revvs plus improved by having sports mode on) and fuel consumption is way high...no one else with this problem seems to have rough running though so maybe I have another issue too??
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To get to this weird o ring I have to get the plenum, fuel rails and bridge off (the bridge being the black plastic thing with the red gaskets??) is his right??
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Is this just on 2.0 or the v6 too?? I have the hissing noise under plenum with bonnet up and the car runs really rough...its an air leak I'm sure but need to work out where and how to fix it...
Mine`s a 2.5 V6 Chris; it`s made that idle-hissing noise for the 2 years I`ve owned it....the 3 o-rings (2 small, 1 large) were really loose and floppy (the large-one fell apart) when I disassembled the breather-bridge from the throttle/manifold so I`d say they hadn`t kept much of anything in (or out) at all. :-[
I had an assortment of plain o-rings to hand so I just found some that fitted tightly (rather than worrying about them not being the 'real' Vx. items)......all the hoses seemed tight and clear, so the idle-hissing sound was the o-rings for-sure because the hissing is no more! :y
I used this as a visual guide: http://www.omegaowners.com/forum/YaBB.pl?num=1152598350
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To get to this weird o ring I have to get the plenum, fuel rails and bridge off (the bridge being the black plastic thing with the red gaskets??) is his right??
We are talking V6 breather bridge (the bit with Ecotec on it)
You just pull the intake pipes away from the throttles, loosen the throttle body bolts a good few turns, lever off the 'Ecotec' cover and undo the bolt hidden underneath, disconnect the breather and vacuum pipes at the back and the breather bridge will then lift up and away from the throttle body, revealing the seal underneath.
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Anyone chasing an air leak and eliminated all the usual places but still poor vacuum ???
I had this recently and stripped it all down to the intake bridge again. I discovered that the threaded brass inserts in the intake bridge were slightly proud of the surface and were stopping the intake manifold sealing properly. Filed the excess brass off and intake vacuum improved from 17" to 19.5"
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is there a list anywhere of the o rings needed to remove/replace the plenum , or do they come as a kit? :-/
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Dont suppose you would be free sometime to show me matchless?? I have already swapped over the plenum/throttle body and egr as a whole unit and the problem still occurs...should changing all that have fixed the issue in theory if its the breather/bridge orings???
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Hi
The "caged looking O ring" in centre of plenum you are refering to is Vx part no: 90467543
They come in a pack of 2 £1.60 + VAT bought some last week.
For info the O rings do not come in a kit
Roger
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Well mines running like crap, idling rough, struggling to accelerate (although this varies and is fine at higher revvs plus improved by having sports mode on) and fuel consumption is way high...no one else with this problem seems to have rough running though so maybe I have another issue too??
Chris, post as a new thread. You would seem to have more than just O ring problems.
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Already have mate...but there is a definite plenum airleak and its a good place to start???
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Hi Guys,
Just a note to let you know that the plenum O'rings (base of plenum to inlet) are available as a pack/kit of 6 O'rings Part# 9118135 from Vx for £ 11.55 List plus VAT :y.
Regards,
P.
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Hey Chris,
It may be a good idea to get the breatrher box O'rings as suggested by B/Roger and also plan for a set of 6 Plenum O'rings, get some carb spray and strip plenum, Clean Idle Control Valve, throttle body and re-assemble with all new O'rings fitted - This will at least eliminate any potential vacuum leaks on Plenum area :y.
Regards,
P.
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Hi Guys,
Just a note to let you know that the plenum O'rings (base of plenum to inlet) are available as a pack/kit of 6 O'rings Part# 9118135 from Vx for £ 11.55 List plus VAT :y.
Regards,
P.
£9.35 +VAT with trade club card :y
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Damn!
Got to get me one of those!!!
Thanks :y,
P.
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I have already swapped over the plenum/throttle body and egr as a whole unit and the problem still occurs...should changing all that have fixed the issue in theory if its the breather/bridge orings???
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Hi Chris,
Try looking into the possiblity that one of your plenum O'rings was not compressed (Mentioned in an earlier PM). This could explain the vacuum leak :y.
Regards,
P.
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Also check the brake vacuum hose from the plenum.
Where the pipe runs by the Aircon pipe it can easily wear through if it's touching, this was the problem on mine when it had a vacuum leak.
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I have already swapped over the plenum/throttle body and egr as a whole unit and the problem still occurs...should changing all that have fixed the issue in theory if its the breather/bridge orings???
Fancy a drive down the A46 to South/East Nottingham?
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Sure Marks DTM when are you free?? :) I'm around most afternoons and some mornings :)
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ok, so I had a look at the spare plenum I have in the garage (the one that came off the v6 in the first place) took the throttle bit off...so I can see the 2 o rings between the throttle body and the plenum...can see no sign of the 3rd special o ring were talking about...there seems to be a hole in the middle underneath the plenum, is that where the o ring would be normally?? If so I'm wondering if the thing is missing completely...if not then where is it??
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Thats it!
That is the 'special' cage type o'ring that has been in discussion. Possible vacuum leak through there!
Regards,
P.
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Will have to go have another look, cant see an o ring at all...
Is the vacuum hose the one that runs out from the right hand side of the lower end of the throttle body?
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Hi Chris,
Look back on the first page of this from Roger - "The "caged looking O ring" in centre of plenum you are refering to is Vx part no: 90467543
They come in a pack of 2 £1.60 + VAT bought some last week.
For info the O rings do not come in a kit
Roger "
Regards :y,
P.
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Click http://www.omegaowners.com/forum/YaBB.pl?num=1152598350
Fourth picture down Chris; the detail close-up lower-right shows the bottom portion of the gaged o-ring, the rest is not visible but is around the circular breather plastic-part that inserts into the hole in the aluminium plenum....I bought one the other day for 90.p at Vx.
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Thanks Debs,
A picture is certainly worth a thousand words :y. Surely if this O'ring is missing it could cause rough engine idle / operation.
Cheers,
P.
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Sorry the hole I was in fact thinking about is on the top of the plenum, where the little breather box plugs in...cant see n o ring on the spare plenum...or would it be in the breather box itself????
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Right yes, thanks Debs :) Picture does indeed help...ok I will have to take the breather box off tomorrow and see what I can see :) I have a feeling though I snapped the original breather box so had to put a replacement on anyway, wouldnt have thought there is that much chance both had dud o rings, but you never know...and I could be wrong in my thoughts there :)
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Follow the link from Debs. This takes you to the service to clean the breather box. The 'cage' O'ring mounts to the plastic projection beneath the breather box and seals inside the hole at the top of the plenum. The O'ring is not just an O'ring as it has an additional piece fabricated into the rubber that seals the breather box projection piece. Check it out :y.
Cheers,
P.
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Sorry the hole I was in fact thinking about is on the top of the plenum, where the little breather box plugs in...cant see n o ring on the spare plenum...or would it be in the breather box itself????
Aren`t we talking about the same thing? ;)
That hole in the aluminium plenum is where the o ring seals alright, but it is held (captive) on/around the short/ circular perforated protrusion beneath the black-plastic breather box....I guess if your not seeing it, t`aint there! :-[
Sorry....my slow typing meant you`d answered already. ;D
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Just been looking at the aluminium plenum that I took off the car...cant look at the breather box itself till the morning when I can see...but at least I know where I'm looking now and replacement cost if its missing is at least peanuts which is good news :)
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ive been studying this thread with great detail, as i have to do mine at the weekend, it all sounds so simple, it looks simple, just hope it is lol. you lot do give people great confidence to carry out repairs on your own car.
richie :)
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Well Richie, I have never done it before and was pretty much just winging it when I swapped the plenum over for a replacement and everything was simple enough...just make sure you partly/totally undo the throttle body to remove the breather box without breaking it...
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Hi guys,
Just wait till you try replacing the spark plugs or worse - rocker gaskets!
Last Saturday I thought I'd replace spark plugs and it was like surgery - all the while hoping to hell that I did not forget to put back anything!
These engines although quite hardy, seem to have been designed for 'install and forget' duty ;D!
Regards,
P.
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Ok got the plenum loosened and the throttle body off, and the breather box off...andfound the caged O ring thing...not perfect as its not complete...so I need a new one anyway...seems there is a Vaux dealer in Gainsborough so hopefully I can get the parts from there :)
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Only a small dealership and they dont have the parts in stock so will have to wait until Wednesday to get them but we shall see then...although getting a car to scrap this weekend so may be able to get the bits off there just to test it :)
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Put plenty of grease around the seal when you fit it so it doesn't tear on insertion.
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Thanks for the tip Mark...any particular kind of grease? When are you free to help Mark? Can get over there pretty much any time next week but I gues it makes sense to wait until after wednesday to see how the new o rings go with sorting out the running issues...although I'm wondering if maybe its leads or dispack causing the main issue :)
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The weather is good this morning (the quiet before the storm no-doubt) so I`m going to fit that caged o-ring to the breather/manifold spigot....no probs. with that job.....but,
There`s an 8/10mm. dia. hose which goes from the black plastic breather bridge to the aluminium breather box (at rear of O/S cylinder bank)....that hose is stuck fast to the aluminium breather nipple (the one with the small orifice); `any ideas on how to pull off the stubborn hose (without doing damage) so I can clean the breather-box orifice?
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Hi Debs,
I couldn't get the hose off mine either. Eventuall pulled and twisted that hard that it snapped off. I just made a slit in the piece left on to release it.
There is enough slack in the hose to trim it and refit. I used a smear of silicone grease when I put it back.
Don't forget, the hole in the breather box is only about 1.3mm
Roger
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Hi Debs,
I couldn't get the hose off mine either. Eventuall pulled and twisted that hard that it snapped off. I just made a slit in the piece left on to release it.
There is enough slack in the hose to trim it and refit. I used a smear of silicone grease when I put it back.
Don't forget, the hole in the breather box is only about 1.3mm
Roger
Brill!...thanks Roger, I`ve (really) pulled and twisted the hose as you advised and it`s come-free; thankfully, without snapping :y
As I suspected the breather orifice is completely blocked; poking a variety of gauge wires into it hasn`t made any progress, so I will run a 1.25mm. drill bit (running-slowly in a flex-shaft chuck) through it to clear.....the breather-hose is also blocked, so carb-cleaner and a 'rodding' through for that too! ;)
The job is the Omega`s equivalent of using 'Vicks'; `able to breathe more easily afterwards. ;D
Thanks,
Debs.
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Hi Debs,
Be carefull not to enlarge the hole or you will have an equivalent of a nasty air leak into the plenum. Try it by hand first with maybe smaller drill in a pin chuck.
I had a job to clear the crud from the small "tube" in the black plastic assembly on top of the plenum. If you look at the projection that fits into the plenum there are two small holes, maybe about 2mm dia. This is where the small breather tube exits to. Make sure both are clear.
Unless you have access to compressed air, I used a tyre pump, it fits neat over where the hose goes on.
Roger
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Arrrgh!!! Had the plenum off to see if the caged o ring needed replacing...figured I wouldnt need the car till the replacement arrived Wednesday...needed the car this weekend, started it up forgetting there was no plenum attached, very rough couple of chugs and it died...so got the plenum all attached up again, started no problem all be it rough as before...
Now the brakes seem to be locked up...barely working like there is no power assistance to them, presumably an air leak or something but I cant see how it suddenly happened as surely the plenum area would not affect this??
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It`s a result!.....the idle is significantly smoother since I renewed the breather bridge o-rings and cleared out the breather-bridge and breather-box/hoses, and as a bonus; the slight oil-weep from the N/S valve cover appears to have stopped. ;)
I was surprised how much 'crud' had aggregated in these assemblies and how difficult the crystalline deposits were to remove.....regular oil changes and checks on the breather system are on my regular to-do list from now-on.
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Arrrgh!!! Had the plenum off to see if the caged o ring needed replacing...figured I wouldnt need the car till the replacement arrived Wednesday...needed the car this weekend, started it up forgetting there was no plenum attached, very rough couple of chugs and it died...so got the plenum all attached up again, started no problem all be it rough as before...
Now the brakes seem to be locked up...barely working like there is no power assistance to them, presumably an air leak or something but I cant see how it suddenly happened as surely the plenum area would not affect this??
...surely that`s got to be 'something' to do with the manifold to servo vacuum pipe, it`s non-return valve or tee-piece Chris....I wonder has something split on that vacuum circuit (perhaps out of sight)?
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Are they the 4 pipes going into the breather box? one thing I did notice was the one of the smaller pipes was only half way on...didnt think much of it...till now! lol
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Are they the 4 pipes going into the breather box? one thing I did notice was the one of the smaller pipes was only half way on...didnt think much of it...till now! lol
No, they are different pipes!....The brake-servo pipe attaches to an 90 degree elbow on the N/S face/edge of the aluminium manifold....from there the vacuum-pipe passes across the top of the engine; just beneath the scuttle, passing via a tee-piece and a non-return valve before reaching the brake-servo....a BIG leak in the plenum/manifold or in that vacuum-servo pipe would leave you with insufficient vacuum for any power assisted brakes.
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Aluminium manifold??? The thing below the plenum with the fuel rails/injectors attached to it?? So maybe I have knocked a pipe off when messing about with the plenum perhaps...the brake servo is the ABS/TC unit bit/area??
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So maybe I have knocked a pipe off when messing about with the plenum perhaps...the brake servo is the ABS/TC unit bit/area??
The brake vacuum-servo is that large(ish) drum-shaped object sandwiched between the bulkhead and the brake-fluid reservior/brake master-cylinder.....The brake-pedal piston (effectively) passes through it. :y
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Aluminium manifold??? The thing below the plenum with the fuel rails/injectors attached to it?? So maybe I have knocked a pipe off when messing about with the plenum perhaps...the brake servo is the ABS/TC unit bit/area??
Sorry Chris....`meant to call it Aluminium plemum. :-[
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Ok got the pipe you mean, nothing obvious there...but while I was checking it out found one of the really thin long little pipes off, so reconnected that and started the car to check...no joy with the brakes, but reminded me that (I doubt coincidentally) when you press the brake pedal in park (and only in park) there is now a clunk noise (like something is loose and moving from under the auto gear lever!! Could this be the park brake come loose or something like that and stopping the brake servo working???
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Ok got the pipe you mean, nothing obvious there...but while I was checking it out found one of the really thin long little pipes off, so reconnected that and started the car to check...no joy with the brakes, but reminded me that (I doubt coincidentally) when you press the brake pedal in park (and only in park) there is now a clunk noise (like something is loose and moving from under the auto gear lever!! Could this be the park brake come loose or something like that and stopping the brake servo working???
That noise (I think) is the interlock which means that you have to have foot on brake to move out of Park. or is it louder than that?
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~Its a definite clunk and it wasnt there before when the brakes worked ok...
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Can you get the car to me next week Chris for a little look?
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Yeah Mark, pretty sure I can but probably could do with sorting the brakes before I do...they do work but barely atm...any particular day better for you? :)
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Well I got the parts from Vaux today...putting them on after lunch...think I may know whats causing the air leak now...when I looked there were 5 o rings which looked to me having not seen them before like they were just worn down...and the 6th one was more like a rubber washer fully filling the slot...so I'm now thinking having seen the new ones are like the 5 worn down looking ones...the 6th one is completely wrong and is causing the air leak...we will see!!
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Right, got the parts on today, not 100% sorted but certainly a lot better and a lot more responsive on acceleration...got a longish trip tomorrow so we will see how that goes...
Still slightly rough so could still do with some help/checking Mark :) So whenever your free let me know :)
Be interesting to see if/how much the fuel consumption increases tomorrow...
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Right, its definitely a lot better running, still a slight niggle here and there under heavy load acceleration sometimes...but not all the time...but hugely better anyway :) May try changing the leads and see how that goes...
At least if it is the dispack I hopefully have a spare on the elite I just picked up :)