Exhaust fumes in car

[xjray]

After a few trips out recently I’ve noticed my clothes smell of exhaust fumes once back home. I haven’t noticed a fume smell inside the car on normal driving until I was stationary for a while in a bit of a jam a couple of days ago and I began to smell it in the car.

This is driving with windows closed and air con running on low fan speed.

The centre section of the exhaust was replaced a few weeks ago so I decided to get the whole thing checked for leaks at a specialist garage that only does exhausts. It was thoroughly checked and no leaks found so I’m puzzled as to where the smell is coming from.

I had a quick trawl on the internet and found one site that described a similar problem, on a Ford of some sort I think, and the suggestion was that it was likely to be coming from perished injector seals. So I’m wondering if the fumes might be coming from the engine compartment, whether via perished seals or elsewhere, and being sucked in via the air intake under the windscreen.

The car has only done 18000 miles from new but obviously all components are now 34 years old.

Any thoughts or suggestions much appreciated.

Ray

[mike020150]

If the engine is still running well, it is unlikely that it has a problem with injector seals. Failures here would result in uneven running and poor performance. The prime suspect has be the recent work done on the exhaust and whether any disturbed joints in the system have been sealed correctly. Another possibility for exhaust smells in the interior is failure of the one-way valves in the ventilation unit below the rear parcel shelf. Describing them as valves is doing Jaguar engineering a favour. In practice, they are several small pieces of foam/cloth lined metal using tape as hinges. After all this time, it wouldn't be surprising if one or more have fallen off inside the unit depriving the system of their intended use and permitting exhaust smells to penetrate the interior of the car. Mike.

[xjray]

Thanks for your reply Mike. The engine runs fine so I guessed the idea of failed injector seals was unlikely, but, having seen it mentioned, thought I’d ask. I will have a look at the one way 'valves' as you suggest.

I joined the fitter under the car while he was checking and neither of us could detect a leak anywhere.

While under there though, I did that find the gearbox centre support bush is shot so it’s going in next week to have that seen to. As they are the ones who fitted the new exhaust section I will ask them to check it again.

Is it possible any extra movement caused by the loose gearbox support could be opening up a small gap somewhere along the exhaust when travelling?

Ray

[davidr]

Hi Ray - I've a dim recollection that the positioning of the exhaust tips is important. They need to be out in the airflow at the corner of the car. If they are too near the centre then the fumes get drawn into the vortex at the back of the car and so can come into the cabin via the flaps as Mike has mentioned.

[xjray]

Hi David, thanks for that.

I had the chrome tips off to clean up few weeks ago. When I put them back I shuffled them as far out as I could but there’s not a great deal of leeway. They are angled to the outside corners. One protrudes just past the bumper rubber but the other sits just under it. The pipes from the back boxes are obviously not the same length (British Leyland made!) and I can’t get that one out any further.

Ray