Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: nigsey1600e on 20 August 2006, 12:05:31

Title: under bonnet hissing
Post by: nigsey1600e on 20 August 2006, 12:05:31

Hi to all

I have just been checking my omega over after noticing a new hissing sound under the bonnet, This is quite loud and seems to be coming from under the pleum chamber. It is more noticeable on tick over, I can make the hissing stop when i squeeze the hose running to the ICV.

does anyone know whats causing this hissing? Sounds to me like a spilt hose or pipe of some sort i know my last 2.5 omega did not do this.

Should it hiss like it does? :-?

If i have to take the plenum off how do i go about this as i have no haynes manual as of yet. And is there any gaskets/o rings i would need to change on refitting.

Any help on this would gladly recived.

Cheers   NEIL

Title: Re: under bonnet hissing
Post by: rpont on 20 August 2006, 12:36:43

There are six 'O' rings under the plenum and then the seals for the manifold but it shouldn't be moving so that the sound stops when you squeeze the ICV hose, everything should be bolted up tight..

What happens if you wiggle the ICV? That has a rubber ring sealing it to the plenum and I'm wondering if that's had it and is letting in air at the bottom.

Title: Re: under bonnet hissing
Post by: nigsey1600e on 20 August 2006, 12:53:29

tried moving the icv thats seems  so tight no air leaking round that and plenum is bolted down tight will have to take the plenum of next weekend ands see whats what

Title: Re: under bonnet hissing
Post by: x25xe on 21 August 2006, 10:56:34

I too, have noticed this om my Omega and have been meaning to ask exactly the same question for some time!

I have not tried squeezing the hose leading to the ICV so cannot advise any further with regard to my engine.

However, what I can say, is that I think I have narrowed the hissing down to the black ECOTEC cover on top of the plenum.  I was thinking that there may well be a seal between this and the plenum which needs renewing.

This hissing that we can hear is vacum generated.

I am hoping that a new set of seals will sort this out and, at the same time, improve economy somewhat.

So, does anyone on here know what seals are used for the plenum?  I know about the six "o" rings but are there any others?  If anyone has a list or knows any advice would be much appreciated.

Title: Re: under bonnet hissing
Post by: Marks DTM Calib on 21 August 2006, 12:01:12

They do hiss a bit at idle......its just the air rushing throught the small opening in the idle valve or the breather ports.

Title: Re: under bonnet hissing
Post by: iggy21uk on 21 August 2006, 13:35:55

Could be  the sequel to the film. "Snakes in a Omega"  ;D

Title: Re: under bonnet hissing
Post by: x25xe on 21 August 2006, 14:40:45

Cheers for that Marks DTM....  at the risk of making a stupid statement, I guess that mine is OK then and there is nothing to worry about?

Title: Re: under bonnet hissing
Post by: Markjay on 21 August 2006, 14:52:32

Quote

Could be  the sequel to the film. "Snakes in a Omega"  ;D

Ssssuch a ssssilly sssstatement....    ;D

Title: Re: under bonnet hissing
Post by: nigsey1600e on 21 August 2006, 16:29:11

Quote

Cheers for that Marks DTM....  at the risk of making a stupid statement, I guess that mine is OK then and there is nothing to worry about?

well that was easlly sorted out cheers

Title: Re: under bonnet hissing
Post by: PLANETNZ on 03 June 2012, 23:58:54

Hi, i see this is 6 years old but im having the exact same problem did you ever manage to find a solution!?