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[terry paget]

2000 Omega 2.5 petrol manual estate
Today my best Omega failed its MOT test on several items, may be beyond economic repair.
It failed on the following items:

emissions lambda reading, never below 1.043. Tester suggested this could be explained by a leak in the right hand central pipe where the pipe enters the silencer box. I had tried sealing with Gun Gum, but clearly failed.

rear offside brake pipe rusty

Suspension component munting prescribed area excessively corroded significantly reducing structural strangth Offside Rear (inner wheel arch)
                                           ditto                                                                                                  Nearside Rear

Looks like it needs a new cat back exhaust system, a new brake pipe, and some welding work on the cat to main section as the cat section flanges are strangely thin.

Please advise.

[Andy H]

I can sell you a 3.2 estate with an MOT until November 2003 Red MV6 3.2 Estate - for sale.

I was asking £700 but it hasn't sold so I am open to offers...

[BazaJT]

A brake pipe[plus ends] is pretty much pennies.Cat back exhaust less than £100[if my saloon one is anything to go by]so it would be the welding that would be the killer for me on cost grounds,but if you can weld then it's basically a no cost option.Just leaves the questions;will a new exhaust cure the emissions problem?and how much do you like/how handy is the car?

[Doctor Gollum]

2000 Omega 2.5 petrol manual estate
Today my best Omega failed its MOT test on several items, may be beyond economic repair.
It failed on the following items:

emissions lambda reading, never below 1.043. Tester suggested this could be explained by a leak in the right hand central pipe where the pipe enters the silencer box. I had tried sealing with Gun Gum, but clearly failed.

rear offside brake pipe rusty

Suspension component munting prescribed area excessively corroded significantly reducing structural strangth Offside Rear (inner wheel arch)
                                           ditto                                                                                                  Nearside Rear

Looks like it needs a new cat back exhaust system, a new brake pipe, and some welding work on the cat to main section as the cat section flanges are strangely thin.

Please advise.

Told you...

The exhaust is the least of your worries, although at £95 at least it's an easy fix. The only welding the car needs is from the rear jacking points to the middle of the rear wheel arches. On both sides.

[terry paget]

A brake pipe[plus ends] is pretty much pennies.Cat back exhaust less than £100[if my saloon one is anything to go by]so it would be the welding that would be the killer for me on cost grounds,but if you can weld then it's basically a no cost option.Just leaves the questions;will a new exhaust cure the emissions problem?and how much do you like/how handy is the car?

Complete cat back exhaust £93 delivered, see recent thread. I have welding gear and a friendly welder, I will ask him if he can do the wheel arch and the flange. Whether that will cure the lambda is an open question. Thanks for the advice on the brake pipe.
The car belongs to my son, and his 4 year old son Tom thinks it is wonderful.

[terry paget]

2000 Omega 2.5 petrol manual estate
Today my best Omega failed its MOT test on several items, may be beyond economic repair.
It failed on the following items:

emissions lambda reading, never below 1.043. Tester suggested this could be explained by a leak in the right hand central pipe where the pipe enters the silencer box. I had tried sealing with Gun Gum, but clearly failed.

rear offside brake pipe rusty

Suspension component munting prescribed area excessively corroded significantly reducing structural strangth Offside Rear (inner wheel arch)
                                           ditto                                                                                                  Nearside Rear

Looks like it needs a new cat back exhaust system, a new brake pipe, and some welding work on the cat to main section as the cat section flanges are strangely thin.

Please advise.

Told you...

The exhaust is the least of your worries, although at £95 at least it's an easy fix. The only welding the car needs is from the rear jacking points to the middle of the rear wheel arches. On both sides.

Fair comment Doc, and thanks for your advice. Now we know where we stand, only spent £35 for the MOT so far. 

[Enceladus]

This concerns a pre-facelift 2.5 V6, doesn't it?

I'm struggling a bit to understand how a hole in one of the centre boxes can affect the lambda reading, as the centre sections are downstream of the cats and the lambda sensors? How would a new exhaust fix that?

If you can't properly weld it yourself then you need to find somebody who knows what they're doing. Used to be that any good independent garage knew how to weld a Carlton. Not so sure where I would go to for an Omega nowadays. Getting that properly and economically fixed and future deterioration prevented is likely the biggest issue you have.

I grow increasingly alarmed about reports on this forum of MOT failures on Omega brake pipes. I've done plenty of mile in older(ish) Carltons and Senators and never had to replace a brake pipe. That said easily repairable.

[terry paget]

I can sell you a 3.2 estate with an MOT until November 2003 Red MV6 3.2 Estate - for sale.

I was asking £700 but it hasn't sold so I am open to offers...

I suppose it's an auto, being a 3.2, and all we know here are manuals.

[Doctor Gollum]

I can sell you a 3.2 estate with an MOT until November 2003 Red MV6 3.2 Estate - for sale.

I was asking £700 but it hasn't sold so I am open to offers...

I suppose it's an auto, being a 3.2, and all we know here are manuals.

It won't be any worse than a £500 Astra

[terry paget]

This concerns a pre-facelift 2.5 V6, doesn't it?

I'm struggling a bit to understand how a hole in one of the centre boxes can affect the lambda reading, as the centre sections are downstream of the cats and the lambda sensors? How would a new exhaust fix that?

If you can't properly weld it yourself then you need to find somebody who knows what they're doing. Used to be that any good independent garage knew how to weld a Carlton. Not so sure where I would go to for an Omega nowadays. Getting that properly and economically fixed and future deterioration prevented is likely the biggest issue you have.

I grow increasingly alarmed about reports on this forum of MOT failures on Omega brake pipes. I've done plenty of mile in older(ish) Carltons and Senators and never had to replace a brake pipe. That said easily repairable.

I have 2 2.5 manual estates, this is the facelift.

In the UK, while the lambda sensor is in the cat section after the cat, the exhaust gases are analysed at the tailpipe, so air leaking in at the central silencer will affect the measured lambda reading.

[Nick W]

A leaking silencer won't be the cause of your emissions fault, although it is a failure by itself. New exhaust is £100 and less than an hours work. Sorting the high lambda number will require some proper diagnosis, but probably won't be too bad.


New cats(I would never buy used ones) aren't particularly expensive, but the costs are adding up.



Brake pipe is a trivial repair, and is common for a twenty year old car. You can't tell how bad a rusty looking steel brake pipe is, so they're listed as failures. Which is what a safety inspection is for. I've replaced several like this, and every one was justified. Smothering them in grease so they can't be examined is a bodge that I think should be a failure all by itself.


The welding is your real problem. It's why I got rid of my car last summer; a critical look at both sills, NS sill end to subframe mount/floor/seatbelt mount, NS wheel arch and quarter panel, front and rear chassis rails meant it wasn't worth fitting the new sills I had in stock. I had already repaired the OS sill end/floor and wheel arch. My car was repairable, it just wasn't worth the time even though it was mecanically strong(recent suspension overhauls, good engine, refreshed interior, everything working correctly). I strongly suspect, because I haven't looked at it, that yours is the same. Most of these cars are at this point in their life where even skilled DIY repairers(like me) won't repair them. Which is why they're not 'classics' - whatever that is - yet. There's still too many of them about in daily use. Give them another 10 years, and the remaining few dozen will be like a Cresta is now. You'll see one at a show and reminisce before moving on to look at something interesting.

[dave the builder]

This concerns a pre-facelift 2.5 V6, doesn't it?

I'm struggling a bit to understand how a hole in one of the centre boxes can affect the lambda reading, as the centre sections are downstream of the cats and the lambda sensors? How would a new exhaust fix that?

any hole in the exhaust will suck air in (venturi ) , the MOT emission machine has it's own lambda sensor (does not use the cars sensors ) so, extra air screws the reading ,results in a fail , even though the cars pre and post cat lambdas are working and adjusting the mix

plug the holes in the exhaust and lambda will return to tolerance 
 

I grow increasingly alarmed about reports on this forum of MOT failures on Omega brake pipes. I've done plenty of mile in older(ish) Carltons and Senators and never had to replace a brake pipe. That said easily repairable.

but the original steel pipe is far better/stronger , you just need to clean and protect brake pipes before taking a car for an mot ,as part of an pre MOT check over.

[Doctor Gollum]

A leaking silencer won't be the cause of your emissions fault, although it is a failure by itself. New exhaust is £100 and less than an hours work. Sorting the high lambda number will require some proper diagnosis, but probably won't be too bad.


New cats(I would never buy used ones) aren't particularly expensive, but the costs are adding up.



Brake pipe is a trivial repair, and is common for a twenty year old car. You can't tell how bad a rusty looking steel brake pipe is, so they're listed as failures. Which is what a safety inspection is for. I've replaced several like this, and every one was justified. Smothering them in grease so they can't be examined is a bodge that I think should be a failure all by itself.


The welding is your real problem. It's why I got rid of my car last summer; a critical look at both sills, NS sill end to subframe mount/floor/seatbelt mount, NS wheel arch and quarter panel, front and rear chassis rails meant it wasn't worth fitting the new sills I had in stock. I had already repaired the OS sill end/floor and wheel arch. My car was repairable, it just wasn't worth the time even though it was mecanically strong(recent suspension overhauls, good engine, refreshed interior, everything working correctly). I strongly suspect, because I haven't looked at it, that yours is the same. Most of these cars are at this point in their life where even skilled DIY repairers(like me) won't repair them. Which is why they're not 'classics' - whatever that is - yet. There's still too many of them about in daily use. Give them another 10 years, and the remaining few dozen will be like a Cresta is now. You'll see one at a show and reminisce before moving on to look at something interesting.

And as you know, pretty much the exact same decision with my Desmond

Either strip it for parts you probably won't use or shop around and scrap it for £180ish towards it's replacement.

[terry paget]

Thank you all for your advice and experience. I thought this particular car was destined to be always free of rust, but I was wrong. This MOT failure has set me back. After 20 years of providing Senators and Omegas for my family, that happy period is over. I now have 2 working Astras, and a Rover Streetwise that came with daughter-in-law. I prefer the big Vauxhalls though.

My other 2.5 estate is also due for MOT now. It seem all right to me, but I must check it out very thoroughly, especially brake pipes!

[Doctor Gollum]

Thank you all for your advice and experience. I thought this particular car was destined to be always free of rust, but I was wrong. This MOT failure has set me back. After 20 years of providing Senators and Omegas for my family, that happy period is over. I now have 2 working Astras, and a Rover Streetwise that came with daughter-in-law. I prefer the big Vauxhalls though.

My other 2.5 estate is also due for MOT now. It seem all right to me, but I must check it out very thoroughly, especially behind the sill covers and rear wheel arch liners!

Fixed