Exhaust putty and the MOT man

[BenzBoy]

Preparing the Merc for its MOT, it has a leaking downpipe at the gasket. We all know what a pig exhausts are, and to be honest I'd rather daub some zorst putty on it rather than mess about with rusted bolts shearing, etc.
Will the MOT man kick up a stink? Or is exhaust putty / bandages MOT-friendly?

[Ratdat]

As long as it doesn't leak, I think it's okay. I've got tests on cars with bodged up pipes, including a gun-gum bandaged back box.

[Mr S]

My MOT station didn't pass mine with the gunge on.... Said it wasn't an MOT standard repair! lol

[garethj]

Putty isn't too good near the engine where the exhaust gases are still hot, much more durable on back boxes.

If you use it, DON'T thrash the engine until you've had the MoT or you'll probably blow all the Gun Gum out!

[BenzBoy]

Cheers chaps. I'll look at the bolts and see if they're of the shearing-off, rusty chocolate variety (I fear so). If it looks like I'll have a mare getting the thing unbolted I'll have to try and bodge it
I suppose I could always make a "heat shield" to mask the bodgery ;D

[Odin]

I've got a years ticket with a fair sized hole caked in putty no problem.

[lebowski]

My Clan exhaust has four bean tins with healthy dollops of Hermetite on it and it passed the MOT fine.

[spacekadett]

The MOT book says it's only a fail if it's a 'signifcant' leak,a little one only a pass and advise. Other than that as long as it's secure you can have as much paste and bean cans as you like

Like the bloke who took my refresher course said 'MOT is minimum standard to be on the road'!!

[rmad]

My MOT man put some on so I could get a pass!

[B-8-D]

as long as there is no "significant leak" theres fec all they can do apart from "advise" ...
si

[st182]

For reference- recent tests on the micra test bed, has revealed the following results so far. Test carried out on rotten joint on flexi coupling:

Putty on its own lasted a week.
Putty with can round lasted about 6 weeks.
Currently on putty, bandage, foil, bean can and 2 clamps cos it snapped in half.

Will let y'all know how long that lasts (unless i managed to get it replaced before it fails again)

[Bioshock]

If it don't leak-They can't fail it

[Nathan]

I did this a few years back but to stop the gum from coming off I put Manifold wrap over the GUM, job sorted and sealed.

[mercmad]

Split the front pipe off back by the trans,then undo the manifold off the head.you can drop the whole lot out the bottom and undo the bolts( 2 of them ) on the bench/floor /whereever.
An oxytorch is the best deal for manifold bolts.
When reinstalling the parts,Use high temp silicone on the head surface and the flange,it will outlast the car!. it doesn't go hard and if you wait for a day or so for it to set up,it will be perfect seal.
I use it all the time on muffler joints too as it allows the pipes to slide together easily.If theres a hole in the muffler i just smear it over the hole,leave it for a few hours and the hole is sealled until I can afford a new one.
By the way,never get gun gum or any other muffler seal in your eyes! it burns like hell.