Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: Toledodude1973 on 23 February 2019, 18:47:59

Title: rusty cat converter
Post by: Toledodude1973 on 23 February 2019, 18:47:59
Looking under the Omega 2.6 today i noticed the heat shield outer casing on the cat converter was crusty and some of it is missing,is this a MOT fail . its not blowing and is it an expensive replacement thanks for any help
Title: Re: rusty cat converter
Post by: Doctor Gollum on 23 February 2019, 19:10:15
Can be secured with a large stainless jubilee clip or removed completely  ;)
Title: Re: rusty cat converter
Post by: Nick W on 23 February 2019, 19:14:11
You'll only ever notice a difference whether it's there or not if it rattles.
So remove them from each cat.


Easy :y
Title: Re: rusty cat converter
Post by: Toledodude1973 on 23 February 2019, 19:36:46
so just break them away and no MOTworries
Title: Re: rusty cat converter
Post by: Alnico Blue on 23 February 2019, 20:49:21
You'll only ever notice a difference whether it's there or not if it rattles.
So remove them from each cat.


Easy :y

Nick . . . this "cat rattle" on my 2.6  I have a loudish rattle only when the car is started from cold , meaning overnight cold.  On cold  start up it rattles like hell for about 20 secs then fades completely after about a minute or 2.   This is coming directly from the drivers side cat from  the heatshield area.
I might try & remove the heat shield as it must be this that is causing the rattle.  I'm guessing as  the cat heats up something must be expanding & the rattle stops.

To remove . . . is it a case of just carefully grinding through the welds & the shield will then come away?

Or am I getting this totally wrong & its something in the cat rattling?  :-\ :-\

Title: Re: rusty cat converter
Post by: annihilator on 23 February 2019, 20:59:22
Depending on how rusted they are you can usually lever them off with a big Screwdriver /bar, however my rattle turned out to be the cats innards which had broken up and needed replacing.
Title: Re: rusty cat converter
Post by: nellys coupe on 23 February 2019, 21:15:38
its not an mot faliure so long as its not blowing, :y
Title: Re: rusty cat converter
Post by: Nick W on 23 February 2019, 23:09:29
You'll only ever notice a difference whether it's there or not if it rattles.
So remove them from each cat.


Easy :y

Nick . . . this "cat rattle" on my 2.6  I have a loudish rattle only when the car is started from cold , meaning overnight cold.  On cold  start up it rattles like hell for about 20 secs then fades completely after about a minute or 2.   This is coming directly from the drivers side cat from  the heatshield area.
I might try & remove the heat shield as it must be this that is causing the rattle.  I'm guessing as  the cat heats up something must be expanding & the rattle stops.

To remove . . . is it a case of just carefully grinding through the welds & the shield will then come away?

Or am I getting this totally wrong & its something in the cat rattling?  :-\ :-\


If it's the shields rattling you won't need a grinder, just some stout gloves to prevent you cutting your hands when pull the shield off. Once you've done that, give the cat body a thump with your fist. If that makes it rattle, the cat is knackered and needs to be replaced. They do tend to make a much heavier noise than just rotten shields though.
Title: Re: rusty cat converter
Post by: Alnico Blue on 24 February 2019, 13:42:32
Right  . . .tested as follows from cold this morning  ;)

started car   . . .noisy rattle from cat below drivers seat  . . .as soon as I touched the shield below the cat  firmly with a gloved hand  . . .noise stopped instantly  . . .took hand away &  noise started again .

so must be the shield .      Not decided if I will remove it as although annoying  . . .it only lasts for a minute or 2 from a totally cold start  :-\ :-\
Title: Re: rusty cat converter
Post by: Doctor Gollum on 24 February 2019, 14:11:03
It will fall off in due course... Wait until it rattles when warmed up and remove it. :y

Wait any longer and the person behind might be claiming off your insurance...
Title: Re: rusty cat converter
Post by: dave the builder on 24 February 2019, 15:05:19
It will fall off in due course... Wait until it rattles when warmed up and remove it. :y

Wait any longer and the person behind might be claiming off your insurance...
how will the car behind prove the part fell off the omega  :P
our roads are covered in car parts that fall off  ,nearly as many parts as pot holes  ;D

personally, i would wire or hose clamp the heat shields back on ,the sooner the cat gets warm ,sooner it works ,less chance of post cat lambda reading rich  :-\
Title: Re: rusty cat converter
Post by: Migv6 le Frog Fan on 24 February 2019, 18:23:06
There is a hell of a lot of heat which comes of cats when the car is running. I would be concerned that binning the heat shields would allow all that heat to damage things under there ?  :-\
Title: Re: rusty cat converter
Post by: TheBoy on 24 February 2019, 18:31:13
There is a hell of a lot of heat which comes of cats when the car is running. I would be concerned that binning the heat shields would allow all that heat to damage things under there ?  :-\
My old MV6 lost all its heatshields years and years ago, including the cat ones.  I reckon I drove it in such a way that the exhaust got pretty hot.

Never had an issue.
Title: Re: rusty cat converter
Post by: cam.in.head on 24 February 2019, 18:33:33
According to my not test station the shields are now part of the test and if originally fitted should be there at mot time.he said he will fail a car with a shield missing .like someone said earlier just jubilee clamp it secure or re screw the lip if there's any lip available to screw to !.
Title: Re: rusty cat converter
Post by: Doctor Gollum on 24 February 2019, 18:36:38
It will fall off in due course... Wait until it rattles when warmed up and remove it. :y

Wait any longer and the person behind might be claiming off your insurance...
how will the car behind prove the part fell off the omega  :P
our roads are covered in car parts that fall off  ,nearly as many parts as pot holes  ;D

personally, i would wire or hose clamp the heat shields back on ,the sooner the cat gets warm ,sooner it works ,less chance of post cat lambda reading rich  :-\
Rest assured, if the come through my windscreen, your insurers will be getting a phone call  ;)
Title: Re: rusty cat converter
Post by: Nick W on 24 February 2019, 19:46:58
There is a hell of a lot of heat which comes of cats when the car is running. I would be concerned that binning the heat shields would allow all that heat to damage things under there ?  :-\


Mine had none of the exhaust or cat heat shields on it due to age/damage/apathy about refitting them. Worked like that for several years with no problems.


There's a huge chunk of metal under the bonnet that isn't shielded which retains heat for hours
Title: Re: rusty cat converter
Post by: Bigron on 24 February 2019, 20:00:19
We never had any such issues before cats had to be fitted - to solve a non-existent problem!
Now, we can't use leaded petrol in cars with cats and so valve stem clearances have to be increased, to the detriment of oil consumption. Once again, lead removal from petrol was unnecessary; but Johnson-Matthey did well out of it.....

Ron.
Title: Re: rusty cat converter
Post by: biggriffin on 24 February 2019, 20:09:00
We never had any such issues before cats had to be fitted - to solve a non-existent problem!
Now, we can't use leaded petrol in cars with cats and so valve stem clearances have to be increased, to the detriment of oil consumption. Once again, lead removal from petrol was unnecessary; but Johnson-Matthey did well out of it.....

Ron.


And still are, just go to the plant in Royston, or the warehouse in Bedford. ;)