Will i die in a ball of fire?

[boyse7en]

Managed an epic workshop cock-up yesterday.
Trying to locate a small leak in the exhaust system, I followed a youtube tip to stick a vacuum cleaner up the car's rear end and listen for the whistle of air. My car has a double outlet rear silencer, so with the vac in one outlet all that was achieved was to draw air in the other outlet.

So i rolled up a rag and blocked up the second outlet, thinking I had this cracked. Turned the vac on and with a slurpy thrruuuppp noise the rag got sucked into the dark depths of the silencer, where it has stubbornly remained. I tried fishing for it with a length of welding wire, removed the back box and blew compressed air into it, tried vacuuming through all the other orifices but all to no avail.

So, if i drive with it still in their, do we think it will...

a) just sit there doing nothing much
b) get blown out when i put my foot down
c) catch fire and turn my car into a mobile BBQ?


TLDR: Managed to get a rag stuck in the rear silencer, will the car catch fire?

[boyse7en]

croyde said:

Have you tried blocking the other outlet with something that won't get sucked in and sticking the hoover on the outlet where the rag went?

Yeah, i tried all permutations of sucking and blowing i could think of. No sign of it.

[boyse7en]

AndrewT1275 said:

boyse7en said:

Yeah, i tried all permutations of sucking and blowing i could think of. No sign of it.

If there is no sign of it are you sure it's in the back box and not in the hoover?

Oh, that's a good point. Never thought of checking the hoover... I suppose it could have done a complete lap of the silencer and gone into the hoover. I'm never that lucky though, so i doubt it. Worth checking though

[boyse7en]

GT9 said:

Use a 600 degree C heat gun, maybe one with an adjustable temperature, the rag should eventually catch fire and burn without damaging the exhaust.
And no, a hairdryer won't work.

Hmm... I've got a Paraffin-fired flame thrower in the shed, d'ya think that would do the job?

[boyse7en]

richhead said:

dont understand the hoover bit, why not just run the engine and listen to where its leaking?
or does it involve something sexual???
genuinely laughing at this

If you run the engine the exhaust gets hot... really finger-burning hot, within about a minute - nowhere near enough time to run your hands along all the joints and connectors looking for a small leak.
The vacuum just draws air in (you could set it blow if the hoover has that option) and you can put your hands all around the still-cold exhaust and feel/listen for a change in pitch that indicates a small leak. Much less painful

[boyse7en]

hidetheelephants said:

I'm just waiting for pictorial evidence, then it may qualify for legendary status along side the how to dispose of a garden shed thread.

As you can clearly see, the rag has completely disappeared inside and is not at all visible.
Any Saab experts out there will notice that the silencer is hanging approximately 1.34mm lower than standard, which is due to the extra weight of the rag.

[boyse7en]

The hoover (actually, it a Miele, my middle-class aspiration showing there) has been checked!

And....


No rag in the bag.

But I've been driving the car around a bit and it hasn't exploded yet. I'll keep checking to see if i get any sooty residue blowing out of the rear end.