Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: GrahamK on 16 November 2025, 12:40:50

Title: Mystery pipe- Please help
Post by: GrahamK on 16 November 2025, 12:40:50
Hi all,

Part way through replacing the oil cooler on a 2003 2.6 DBW Omega.

The usual skinned knuckles and difficulties on areas you don't expect, but generally going fairly well. I will do a fuller report later.

However, I have one problem in that I have a mystery pipe that I don't recall disconnecting and I don't know where it goes! Help please.

It's about a 1/2" rubber pipe. No evidence of a pipe clip, so I don't think its a water pipe.

https://photos.fife.usercontent.google.com/pw/AP1GczPtZYzAQzFBeRvITjc2MyjZp6fjf3njTYIsx8xLgT-idnMiP9mQX-4x-A=w933-h1239-s-no-gm?authuser=0

The pipe with the blue tape.

It is not one of the 4 that attach on the back of the plenum, or the main vac hose with the union that connects onto the plenum, or one of the two coolant pipes that connect onto the throttle body.

I also changed the Heater by-pass valve, but 3 pipes have gone back onto there.

I don't remember a pipe on the fuel manifold.

Any ideas?




Title: Re: Mystery pipe- Please help
Post by: Dave G on 16 November 2025, 12:52:39
Does it look like this?? No evidence of a pipe clip or clamp etc. ?

(https://i.postimg.cc/rpBWh1KY/oddpipe.jpg)

I posted a similar question a while back on my clattery noise topic and mine turned out to be a breather pipe from the transmission. Just a thought…
Title: Re: Mystery pipe- Please help
Post by: Dave G on 16 November 2025, 12:54:01
I ask that question because I can’t see your image in the post.
Title: Re: Mystery pipe- Please help
Post by: GrahamK on 16 November 2025, 13:01:14
Hi Dave G,
Thanks for the reply. I don't think it's that, I see it on , I think. I need to take the fuel manifold off again, I just can't see.
Title: Re: Mystery pipe- Please help
Post by: Dave G on 16 November 2025, 13:10:16
Just tried on another computer and your image just shows as a black & white ‘no entry’ sign.
Title: Re: Mystery pipe- Please help
Post by: GrahamK on 16 November 2025, 13:22:03

Hi Dave,

i'll see if I can get the image to work for everyone else.
Title: Re: Mystery pipe- Please help
Post by: GrahamK on 16 November 2025, 13:27:09
try this please.

https://photos.app.goo.gl/BvRVYgkWE5R9p6pd8

Graham.
Title: Re: Mystery pipe- Please help
Post by: Dave G on 16 November 2025, 13:30:43
I see it now. I reckon it’s the same pipe.
Is this auto transmission ??
Title: Re: Mystery pipe- Please help
Post by: GrahamK on 16 November 2025, 13:36:32

Hi Dave.
Yes Automatic.

https://photos.app.goo.gl/Wz1fvCWQPLfmcF1D9

another photo showing the pipe in question and what I think is your pipe.
Title: Re: Mystery pipe- Please help
Post by: Dave G on 16 November 2025, 13:43:18
Well, unless I’m corrected by someone more knowledgeable I’d say that’s the same one.

Seems to come from left (passenger) side of the transmission, hoops over the back of the engine towards the drivers side then seems to go down to nowhere.

No evidence of a pipe clip, hose connection or anything. Just seemed to tuck away at the back of the  engine. I was informed that it’s an auto transmission breather pipe.
Title: Re: Mystery pipe- Please help
Post by: GrahamK on 16 November 2025, 13:46:06
Hi Dave,

I've presumed that your yellow arrowed pipe connects to the plastic union just to the left of it.
Now I think you don't mean that, but the pipe is just an open ended breather of some type.
Is that correct?
Title: Re: Mystery pipe- Please help
Post by: Dave G on 16 November 2025, 13:54:02
Yes. Spot on. It doesn’t connect to that valve. It just pops down into the gap in front of that shiny coolant transfer pipe.

Seemed odd to me at the time but…
Title: Re: Mystery pipe- Please help
Post by: GrahamK on 16 November 2025, 13:59:24
Hi Dave,
Thanks for your help.
I've wasted the last 3 hours work backtracking, but I am satisfied with the solution.
You're right, it seems odd to me too. I've certainly never noticed it before.
Cheers anyway.
Graham
Title: Re: Mystery pipe- Please help
Post by: Dave G on 16 November 2025, 14:06:30
Cheers!!

 :y
Title: Re: Mystery pipe- Please help
Post by: YZ250 on 16 November 2025, 14:23:34
I agree with Dave.  :y  If the pipe has no home, and more importantly appears to have never had a home, I'd agree that it's the transmission breather pipe. It just tucks up randomly behind the engine, as you have found. That one catches a few people out.  :y
Title: Re: Mystery pipe- Please help
Post by: STEMO on 16 November 2025, 15:28:08
try this please.

https://photos.app.goo.gl/BvRVYgkWE5R9p6pd8

Graham.

(https://i.ibb.co/KjxdKrb7/IMG-0984.png) (https://ibb.co/nsM9PL6f)