exhaust fumes in cabin

Dilbert75

noticed this before but never paid much heed - when stationary with heater on, there's a slight smell of exhaust fumes. However I ran the car with heater on today just to keep the battery up and when I got in the smell was quite strong. Got the Carbon Monoxide alarm from the house and sat into the car with it. Within a minute it went off with a reading of 250 odd ppm - over 100 is supposed to be very dangerous. Car is 2000 Octavia 1.6glxi, generally in good enough nick but this is a big problem - hoping its easily fixed. Had a look around engine bay with engine running but couldn't find any sign of obvious gas leaks. Any ideas anyone?

slimjimmc

Any falling outs with the wife lately, changes to your will or life assurance ?

Does the exhaust sound like it's got a hole or a leaky joint anywhere?

mike65

A leak in the exhaust is usually as easy to hear as it is to smell. You could do worse than get on the ground (yes really!) and have a listen under the car.

mathepac

I would suspect a leak somewhere around the exhaust manifold / exhaust manifold gasket. Due to its location, smells and gases leaking out from there could travel the short distance to the passenger compartment air-intake in the scuttle panel under the windscreen.

nmacc

Exhaust holes can be hard to find. The best way of tracing them is to wind down the windows (what, in this weather?) and back into a garage or between two close walls. You'll hear the change in note as you reach the leak.

I don't know enough about the chemistry to say whether that CO reading suggests a leak prior to the cat or not. There are very few holes in the floor to let in fumes and it may be that you have a leak at the manifold that's getting in through the dash or gear gaiter.

Can aerodynamics can be a bit weird. I've had problems in the past with boot & tailgate seals. When the windows were closed and there was a positive pressure in the car, then no fumes came in. But if the sunroof was opened then we had fumes and no leaks in the exhaust. This happened with a Renault 5 and also a Mercedes 190. Odd.

littlevillage

I had the same issue in my car. 02 Volvo diesel

If the car was stationary and running I would have to turn off any fans cause I'd be choking with the fumes.

Issue was slight crack in the Exhaust.

I didn't actually go to the garage until the crack got soo bad that it was effecting Turbo pressure and car was getting really slow.

Garage were looking for 600 to replace that part of the exhaust ... in the end they put a weld in it for me and it only cost 90

Dilbert75

Any falling outs with the wife lately, changes to your will or life assurance ?

No unless you could growing a handlebar moustache for Movember!

A leak in the exhaust is usually as easy to hear as it is to smell. You could do worse than get on the ground (yes really!) and have a listen under the car.

Exhaust holes can be hard to find. The best way of tracing them is to wind down the windows (what, in this weather?) and back into a garage or between two close walls. You'll hear the change in note as you reach the leak.

I've had the engine running and looked around the engine bay, where I thought I could hear some sort of blowing sound - but I wasn't sure (and the pipes were hot so I wasn't going to put a paw in there).

I would suspect a leak somewhere around the exhaust manifold / exhaust manifold gasket. Due to its location, smells and gases leaking out from there could travel the short distance to the passenger compartment air-intake in the scuttle panel under the windscreen.

Issue was slight crack in the Exhaust.

These are fitting in with my way of thinking - I'm hoping its not going to turn out to be a case of a damaged front section - cat converters are not cheap. The exhaust readings in the NCT (two months ago) were fine though???

Thanks for all your suggestions so far - I'll have a look maybe at the weekend (or whenever winter ends).