Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: JasonH on 18 July 2006, 20:08:58

Title: Exhaust manifold leak?
Post by: JasonH on 18 July 2006, 20:08:58
I seem to have a slight metallic farty sound  :-[ when the engine is underload, also at high revs there is a slight whistle.

I've only just replaced the driver's side manifold gasket (V6) to cure a leak when cold - which it has. The gasket was in a fairly poor way but only leaking a little.

I've also found a hole in the back box and replaced that too.

But there's still a leak - I think.

Stationary I can't hear it at all. I've spent quite a bit of time listening whilst someone puts their hand over the end of the exhaust pipe - but nothing. Rev'ed away and nothing.

The EGR looks and sounds fine.

I think the noise is coming from the passenger side and I can clearing hear it with the windows open when accelerating in built up areas (sound reflecting off the houses).

My questions are:

1. Do the manifold gaskets tend to fail at around the same time?
2. Is the sound typical of a manifold gasket or is there something else worth checking?
3. If (as on the driver's side) all the exhaust studs come out when I try to undo the nuts is it possible to change the manifold gasket on the passenger side without moving the engine or removing the head?

Cheers
Title: Re: Exhaust manifold leak?
Post by: Steve W on 18 July 2006, 20:16:09
Did you check the manifold was still all intact? They have a habit of cracking. Plenty of police ones have had that, my dads 2000 2.5 with 40k has had it amongst others. On my dads one the noise disappeared when the car was hot as the manifold expanded, filling in the crack.
In the end Vauxhall paid for them to be changed.
Title: Re: Exhaust manifold leak?
Post by: JasonH on 18 July 2006, 20:22:45
It's hard to tell without getting right in there and removing the heatshields.

As I understand it the manifold design was changed and as mine's a year 2000 I'm really hoping mines the newer type manifold. The noise isn't heat dependent - it's fairly constant.
Title: Re: Exhaust manifold leak?
Post by: markey mark on 18 July 2006, 21:52:04
its a barsteward to do but is poss  ;) i have done mine !! 8-)
Title: Re: Exhaust manifold leak?
Post by: JasonH on 18 July 2006, 22:03:11
You've done the passenger side - nice one.

Did you have to move the engine? How did you get the manifold out?
Title: Re: Exhaust manifold leak?
Post by: nixoro on 19 July 2006, 11:32:27
Quote
I seem to have a slight metallic farty sound  :-[ when the engine is underload,
Cheers

I seem to have a similar problem but I put it down to having a missing stud at the moment, due to the thread being knackered, the last time I had the gasket done at Bosch they must have breaked it up only the last time I removed the manifold heatshield I found the stud sitting on the manifold.

Should have really sorted this when I removed it last.

Might be worth checking the studs.

HTH
Title: Re: Exhaust manifold leak?
Post by: JasonH on 19 July 2006, 14:17:15
OK will do - but you have corroborated my suspicion that it's the exhaust manifold leaking.
Title: Re: Exhaust manifold leak?
Post by: markey mark on 19 July 2006, 16:58:02
yea done mine  ;) didnt move engine at all and really struggled to manipulate it round the abs !! moved as much stuff out the way as poss  8-)
Title: Re: Exhaust manifold leak?
Post by: JasonH on 19 July 2006, 18:13:30
Well that's good news - it is possible - cheers.
Title: Re: Exhaust manifold leak?
Post by: nixoro on 20 July 2006, 11:32:54
Another thing that maybe causing the farty sound could be caused by a slack accelerator cable not 100% sure.

Could someone confirm this as it was suggested over on the other site.

Many Thanks in advance.

Roy
Title: Re: Exhaust manifold leak?
Post by: Sir_Mixalot on 21 July 2006, 12:15:22
slack accelerator cable causing a funny sound?? - I can't see this being possible?
Title: Re: Exhaust manifold leak?
Post by: nixoro on 21 July 2006, 12:19:21
Quote
slack accelerator cable causing a funny sound?? - I can't see this being possible?

Cheers for the response Sir_Mixalot

It was just something I read and was not sure about, still glad i asked.