E220CDi Catalytic Converter Problems

[daviddharris]

Hi, I have had 2 cats replaced on my 2001 E220cdi - both done under warranty as Merc stated that it was a known fault. Bad news though, its (they?) have gone again! Apparently, the ceramic breaks up and blocks the exhaust, which causes lots of black smoke and a loss of aceleration. I have the car in a MB dealer now and am trying to get them to change it under the same warranty claim as before. Has anyone else had this issue? I understand from a US forum site that they have had the same problems.

 

[Bobby Dazzler]

David. Are you just hearing noises, or are losing power?

Reason I ask is that our ML270 CDi had new cats at about 14 months old. I could hear the tell tale signs coming back 18 months later just as it did before, and I had concerns that they'd finally go after warrant expire.

Dealer couldn't find cause but believed the cats were fine. After a couple of attempts it turned out to be a bracket that had worked loose, but couldn't be seen from a visual check - had to take stuff off to see the cause of the problem. Noise went away afterwards.

If it's just the noise you can hear, and you've not experienced a lack of power, then it may be worth checking brackets too.

 

[daviddharris]

Hi Bobby Dazzler!
Yes, a BIG loss of power when trying to acelerate (it struggles up hills...) and lots of black smoke too.

 

[rajinder_1]

if they have gone that fast there must be anothe factor causing this!!!

 

[Parrot of Doom]

If Mercedes won't pay for them, cut the cat housing open, gut the innards, and weld it shut. You don't need it on a diesel.

Just make sure the cut is on the topside, where an MOT man can't see it.

I wouldn't be surprised if they've broken prematurely because they weren't bedded in correctly. I was always told to run the exhaust hot for 30 minutes (idling), and then drive very carefully for the first few hours.

 

[Dieselman]

Theres no need to disguise the cut in the Cat box. One isn't required so it isn't covered in an MOT test at all.

Cat's breaking up is pretty common on all MB cars with close coupled cats. They can spit back scoring the bores so best not left.