w124 e220 downpipe and catalyst

[d215yq]

Hey all,

I've noticed a whirring and rattling getting louder on my 220 coupe so looked underneath and found the downpipe is rusty and loose just behind the front wheel where it goes from two pipes into one.

after a few searches on the internet + this forum i'm surprised to see this is a very long section and it incorporates the cat as well . The cat seems fine, and doesnt rattle, so considering the damaged part is a long way from the cat is there any way of buying a cheap downpipe section and welding it or shd a backstreet garage be able to simply weld the broken part together?

TIA as ever!

Ben

 

[jibcl500]

Ive seen repairs on many exhausts and many have been done very well, find a good welder and ask them to fix it, the exhaust will need to be removed first though.

jib

 

[d215yq]

Thanks Jib, will look for a good welder.

Is there some form of metal casing around this exhaust section or a double lining. i ask as despite a whole lot of rusty metal around the exhaust being very loose and falling off, other than the metallic rattle between 1200 and 2000rpm, the car is very quiet and smooth and economical so i presume the downpipe is not actually blowing. Maybe this is a rusted heatshield for the downpipes or some sort of protective casing that can be cut off altogether?

 

[turbopete]

theres often a protective tin shield around the cat that breaks loose and rattles at those kinds of rev ranges. can be cut off but best welded back on if possible to avoid possible impact damage (from stones etc) to the cat!

 

[bouncer]

Thanks Jib, will look for a good welder.

Is there some form of metal casing around this exhaust section or a double lining. i ask as despite a whole lot of rusty metal around the exhaust being very loose and falling off, other than the metallic rattle between 1200 and 2000rpm, the car is very quiet and smooth and economical so i presume the downpipe is not actually blowing. Maybe this is a rusted heatshield for the downpipes or some sort of protective casing that can be cut off altogether?

On the original pipe there is an heatshield that looks like a double outer pipe, this design is to keep the heat in the pipes to make the cat reach temp quicker. Ive seen this cut off older rotten systems.
On some aftermarket parts this double lined pipe is actualy an expansion joint because the inletpipes are of different lengths and expansion can cause the twin downpipes to split if they are one piece and different lengths.

sTeVe

 

[d215yq]

Thanks for responses guys, to try and explain better, just after the twin downpipes have merged into one there is what looks like a join from this now single pipe to the cat section, and on the side of this join towards the downpipes there is loads of loose rusty metal around the pipe that is split and falling off.

As there is actually no join here and the whole thing is one piece i guess the "join" i'm seeing is actually just a join in the outer heat insulation that Bouncer is talking about.

I think the system is original so presumably i can just tug this casing off (its that loose!) and it wont cause any issues other than a slightly colder CAT?

 

[teddycatkin]

Ben ---I wonder if/how you solved your problem with the heatshield?

 

[d215yq]

An Update...

Ben ---I wonder if/how you solved your problem with the heatshield?

Hi teddy, I managed to split the heatshield and took as much as I could off. I couldnt get the top half off but managed to wedge what was left into place so it didn't rattle and, touch wood, the rasping noises have stopped

 

[teddycatkin]

I have mine secured with jubilee clips at present --if it goes worse then I will just cut it off all together --its only funtion is to help warm the cats up faster as long as the cats are OK leave them ?