C270 cdi pre cat rattle and turbo leak when hot

stue7380

New Member
Joined
Mar 18, 2009
Messages
6
Reaction score
0
Hello, i need help!
My C270cdi has developed a rattle at the 1st cat so i assume its knackered. Can anyone tell whether or not i can remove the insides and rely on the 2nd underfloor cat to do its job and pass the mot?
Also when the car is cold, apart from the rattle the car is fine, however when hot the turbo gasses seam to then leak as i here wooshing through the air vents in the cabin and their is a significant loss of power. Why does the car perform normal when cold but not when its hot?
 

television

Always remembered RIP
Joined
Mar 14, 2005
Messages
164,073
Reaction score
331
Age
86
Location
Daventry
Your Mercedes
2002 SL500, 216 CL500, all fully loaded
Many car will pass the MOT with 1 CAT removed
 
OP
S

stue7380

New Member
Joined
Mar 18, 2009
Messages
6
Reaction score
0
  • Thread Starter
  • Thread starter
  • #4
Thanks, is it likely that the loose bits are blocking the second cat?
Will i be able to simply empty these out when i remove the pre cat and its internals?
 

television

Always remembered RIP
Joined
Mar 14, 2005
Messages
164,073
Reaction score
331
Age
86
Location
Daventry
Your Mercedes
2002 SL500, 216 CL500, all fully loaded
You may have to work backwards, that is remove the rear box so that you can get the front one off, the CAT is as soft as butter and providing that you can get a rod or something down the pipe then it will break up easily, any loose bits in the second box should just fall out, do not bang it though
 
OP
S

stue7380

New Member
Joined
Mar 18, 2009
Messages
6
Reaction score
0
  • Thread Starter
  • Thread starter
  • #6
Thanks, i will try this at weekend. Fingers crossed!
 
OP
S

stue7380

New Member
Joined
Mar 18, 2009
Messages
6
Reaction score
0
  • Thread Starter
  • Thread starter
  • #7
I have removed the 1st cat, found the unit had completely failed all that was left was a large ball of the honeycomb stuff that was giving the rattle and probably blocking the exhaust at times also. Now removed and refitted, car runs ok now but the turbo still leaks air under throttle. Not sure where the leak is or whether the second cat is blocked too,nothing came out from the second cat when i removed that section carefully.
Any idea's regards turbo air leak?
 

turbopete

Senior Member
Joined
Feb 4, 2009
Messages
14,204
Reaction score
328
Age
46
Location
Spennymoor
Your Mercedes
2010 '60' Ford Mondeo 2.0TDCi Zetec (sorry)
Many car will pass the MOT with 1 CAT removed

most diesels pass the mot without any cats! never tried this with a twin cat diesel but ive removed dozens of single cat equipped cars' cats, to the extent where i started to wonder why they even put cats on diesels, as they seem to make little or no difference to the readings for the mot test
 

Xtractorfan

Senior Member
Joined
Nov 16, 2007
Messages
6,084
Reaction score
156
Your Mercedes
S class
Do they still do readings on the diesels, I thot they had stopped doing readings on diesels ...
 


Save 30% on RAC Breakdown Cover
This year...next year... and every year you stay with RAC
Prices start from only £35.35*
This offer is available to all MERCEDES CLUB members and their immediate family**
Top Bottom