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?

[DKS]

I'm sorry but I wished I was there to see that!

I think it's probably a bit risky, back boxes can get very hot. Maybe try a few high revs at temp. with an extinguisher on standby?

[croyde]

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?

[Hoofy]

Can you cut open the backbox and then weld it up afterwards?

Could also try pushing those bendy sink unblocking wires through the other end?

[GiantEnemyCrab]

Leaf blower and duct tape to the exhaust, blow it back out.

[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.

[Super Sonic]

I would imagine this would be considered a modification. Don't forget to inform your insurance company.

[evil.edna]

I can see this becoming a "stage-5" remap technique for all 335d.

[Hoofy]

A bit more extreme - remove the backbox, pour petrol in, light it, run away, let it burn out, shake the remaining ash out? (Might damage the baffles although you'd think that would all burn up through normal driving if it were that flammable.)

[Stick Legs]

[Sheepshanks]

Hoofy said:

A bit more extreme - remove the backbox, pour petrol in, light it, run away, let it burn out, shake the remaining ash out? (Might damage the baffles although you'd think that would all burn up through normal driving if it were that flammable.)

On the off chance you might get desperate enough to try this, bear in mind that it's likely to expode rather than burn.

[GT9]

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.

[AndrewT1275]

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?

[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?

[hidetheelephants]

Probably won't catch fire, more likely to block the back box. You could encourage it to catch fire by going for a longish italian tune-up, it won't set fire to the rest of the car because it's designed not to, that's why there's a big air gap and heat shields around the catalyst etc. although no doubt some safety karen might call the fire brigade once you start generating a smoke screen. A less silly way round it would be to remove the back box and blow the rag out the other end.

boyse7en said:

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?

That would work, those things are very good at heating stuff up but definitely remove the back box from the car before attempting this unless you want to set it alight.

Edited by hidetheelephants on Monday 13th May 11:39

[thebraketester]

Seems a good time to buy a flexible endoscope….

[AndrewT1275]

boyse7en said:

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

Is this for the Saab in your profile? If so then they have 2 different twin tailpipe exhaust options, one is separate back boxes on either side of the car each with a single tailpipe, the other is a single backbox with twin tailpipes. If yours is the single backbox option then the rag is most likely in your hoover where it has been quietly winning this epic game of hide and seek.

[Hoofy]

Sheepshanks said:

Hoofy said:

A bit more extreme - remove the backbox, pour petrol in, light it, run away, let it burn out, shake the remaining ash out? (Might damage the baffles although you'd think that would all burn up through normal driving if it were that flammable.)

On the off chance you might get desperate enough to try this, bear in mind that it's likely to expode rather than burn.

Key bit highlighted.

[Sheepshanks]

Hoofy said:

Sheepshanks said:

Hoofy said:

A bit more extreme - remove the backbox, pour petrol in, light it, run away, let it burn out, shake the remaining ash out? (Might damage the baffles although you'd think that would all burn up through normal driving if it were that flammable.)

On the off chance you might get desperate enough to try this, bear in mind that it's likely to expode rather than burn.

Key bit highlighted.

There won't be chance to run away!

This is what'll happen, although the smiley is incorrectly named! :

I speak from experience......