Exaust fumes getting into car

Penguin · Unread post by **Penguin** » 08 Mar 2010, 08:24

I tried hijacking someone else's thread with this but received no response, so thought I'd try in its own thread!!

I've been meaning to post this query for some time and it kinda fits in here I guess.

Ever since I have had the car (18 months now) I get fumes in the car if the window or sunroof are open. Doesn't matter which window. Its only in certain conditions i.e. running at 30mph-ish or less. Its really bloody annoying. If I have the sunroof and a window open it is less noticeable, but still there.

Is this common for a Mk1 Xant or is there a particular problem with mine?

Unread post by **CitroJim** » 08 Mar 2010, 08:46

My first thought would be a leaking "brillo pad", the exhaust to manifold joint.

Have a look at the joint and see if you can see fresh soot around it. Another clue to the failure of this joint is being able to smell exhaust fumes under the bonnet.

Another favourite spot, if yours has a cat, is the rear cat to mid-section pipe joint.

Unread post by **citroenxm** » 08 Mar 2010, 10:14

Is there a gommit or hole in the boot section??

Tow bar fitted? If so there be a hole for the electrics to run through into the car.. the hole for this? Check its all sealed properly

Paul

Penguin · Unread post by **Penguin** » 08 Mar 2010, 10:47

Thanks for the tips guys. Are leaky exhausts not usually picked up at MOTs? As you can probably tell me and mechanicals are not the best of bed-fellows!

Paul, If there were a hole anywhere wouldn't I get fumes even with windows/sunroof closed? There is not even the slightest whiff until I open something.

Edit: So I guess it isn't a trait of the marque then!

Unread post by **CitroJim** » 08 Mar 2010, 10:50

They can potentially miss the manifold blowing although good ones have a sniff under the bonnet. Normally this results in an advisory if the leak is not of biblical proportions.

HDI · Unread post by **HDI** » 08 Mar 2010, 11:01

Just to give an idea of how much an exhaust can leak without it being detectable until the windows or sunroof are opened , the exhaust on mine has completely broken away at the rear silencer box connection and there is no smell of fumes until a window or the sunroof is opened !!

You will have an exhaust leak somewhere.

Unread post by **Old-Guy** » 08 Mar 2010, 11:15

What's happening is that opening a window or the sunroof when the car is moving, reduces the 'cabin' air pressure. If there's any sort of hole from an area of higher pressure outside into the cabin, air (and any exhaust fumes) is sucked into the car. You can reduce the effect by making sure the facia vents are open.

Another place to check is where the pipe goes into the front end of the rear silencer - the favourite place for exhaust failure - if it's not blowing badly, it's easily missed at the MoT. When you put a new box on, it's worth spraying the ends of the silencer with heat-proof paint (e.g. wood-burning stove paint). The box is made of coated steel, but the coating gets burnt off when the pipes are welded into it, leaving a ring of naked, stressed and already oxidised steel around the outside of the weld, which immediately starts rusting, and is why the pipe and weld breaks away from the box.

HDI Dave · Unread post by **HDI Dave** » 08 Mar 2010, 12:12

HDI wrote:Just to give an idea of how much an exhaust can leak without it being detectable until the windows or sunroof are opened , the exhaust on mine has completely broken away at the rear silencer box connection and there is no smell of fumes until a window or the sunroof is opened !!
You will have an exhaust leak somewhere.

I have to agree with this fellow,and old guy above. I have exactly the same symptoms. and, my exhaust pipe has just completely snapped off at the rear box,leaving the pipe resting on a bar/brace? that is bolted to each side of the car.
Open the windows and monoxide city lol.

Mine's been badly stick welded (burnt the flange away), so a lot of bodging for me will be needed.
I'm thinking of putting a metal sleeve\tube inside the back box and the pipe,bit of paste,maybe a bandage and some jubilees..don't care how pretty it is

Seems to be a common problem,that's where it snapped before,so it had a new zorst,and here we are again...the pipe's under a lot of tension at that joint upon inspection.

HDI · Unread post by **HDI** » 08 Mar 2010, 12:36

Yeah , it is common on Xantia's.Poor design really especially when the rest of the system is fine. I have repaired the one on my HDI once already and it's lasted 3 years.The flared pipe flange has broken up this time so it would be a PITA to repair again. I've just found a repair pipe on ebay, that doesn't have a centre silencer , for £18 odd + shipping , so I will go that option this time.

Unread post by **citroenxm** » 08 Mar 2010, 12:45

I wouldn't worry about a centre silencer on the HDi what so ever!

The original XUD in the Xantia was only back box equipt, and the HDi is a 70% more cleaner engine so Id do away with it..

If you study the "Exhaust Tunnel" you'll see that its not really wide enough for a center box, just a Round style 'cat' near the front..

Paul

HDI · Unread post by **HDI** » 08 Mar 2010, 13:04

Turbo diesels are quiet enough without that centre box. In fact , even with the exhaust broken as it is the noise is still low !!

MikeT · Unread post by **MikeT** » 08 Mar 2010, 14:07

I agree with Jim, it's probably the flexi-joint gasket between manifold and exhaust. I had this on my first TD with the exact symptoms you describe.

If you intend to keep the car, buy the genuine kit from Citroen as it's a high quality gasket (unlike the 3rd party offerings) and all new parts including bolts, nuts, cups, washers etc.

Penguin · Unread post by **Penguin** » 09 Mar 2010, 08:12

Thanks for all the help guys. I'll have to get this looked at before the summer.

citronut · Unread post by **citronut** » 10 Mar 2010, 08:05

you can buy the woven wire/brilo pad type of sealing ring from the likes of GSF, they use to sell the full kit with an asortment of nuts,bolts, springs and washers,

the one to steer clear of is the nasty fiber type a lot of exhaust centres supply, as it will break up in no time at all

regards malcolm

HDI Dave · Unread post by **HDI Dave** » 26 Mar 2010, 09:58

I've bodged my exhaust back box,as the smell was headache inducing..cut an old computer case up to make a sleeve as the flange was shot:

It's cured 75% of the pong.
Where is this 'brillo' seal and how easy is it to get at/fit?

Ta,Dave.