Omega Owners Forum

Chat Area => General Discussion Area => Topic started by: GraemeT on 06 November 2008, 17:20:51

Title: Vectra -Resonating cat - sounds like it's blowing?
Post by: GraemeT on 06 November 2008, 17:20:51

Hi all

2.0 DOHC 1999 Vectra - only had a few days and today was the first chance to have a look.

I've taken off the heat shield and there is no leaks from the manifold or the downpipe/manifold gasket.

Getting under the beast the sound is coming from the cat! There are no leaks around the cat (felt all the may round it) but there is a resonating sound coming from it - if you hold your hand on it then you can feel the vibartions.

The 'blow' sound is in time with the engine - I'm puzzled as to what this sound could be - any suggestions.

Graeme

Title: Re: Resonating cat - sounds like it's blowing?
Post by: Phil B on 06 November 2008, 17:23:47

I had the honeycomb crack in my old escorts' cat. Is the noise deffo coming from inside?

Title: Re: Vectra -Resonating cat - sounds like it's blowing?
Post by: Auto Addict on 07 November 2008, 06:25:59

Sorry, but moving this to General Chat as it's not an Omega.

Title: Re: Vectra -Resonating cat - sounds like it's blowing?
Post by: GraemeT on 07 November 2008, 07:27:03

Whhops - what a typo!

It is an Omega - duh-oh me :-)

Yup - the noise is 100% coming from the cat and there are no leaks anywhere - with the car on the ground it is hard to identify and appears to come from the front pipe/manifold junction area - once you get under the car it is easily ID'd as the cat

Graeme

Title: Re: Vectra -Resonating cat - sounds like it's blowing?
Post by: Gaffers on 07 November 2008, 08:57:54

If the flexijoint is leaking it is difficult to 'feel' it.  I would say if it defo sounds like its blowing from that region that the flexijoint may be suspect, otherwise the blow may be on top thus difficult to feel.  Had the same thing on a 2.0 veccy myself and once it came off it was obvious as the flexijoint just crumbled  :-[

Title: Re: Vectra -Resonating cat - sounds like it's blowing?
Post by: GraemeT on 08 November 2008, 08:23:17

Hi there

it's definately not the top of the cat as I can feel right around it - I'll have a go at lashing soapy water onto the (cold) flexi-join and see if I can spot any bubbles.

Thanks

Graeme

Title: Re: Vectra -Resonating cat - sounds like it's blowing?
Post by: GraemeT on 15 November 2008, 17:06:08

None the wiser here - there is no leak from the flexi join, nor around the manifold, down pipe - anywhere. The noise is a deep 'tonk' - just like you would expect from a blowing exhaust. Local garage has now perused it and thinks that it is simply a resonation within the cat itself - so nothing to worry about for the MoT - just kind of noisy when starting

Graeme