marktan

Out of curiosity, has anyone replaced their stock catalytic converters on their S600 (or other M275 engines)? If so, with what, and at approximately what cost? I'm at just over 90k miles, so the federal 80k emissions warranty does not apply. Will these magnaflow universal cats that I see for $120/each work???

I'm not 100% sure either of mine is bad...no errors, but I'm getting a soft exhaust drone at around 1200rpms light throttle, the "smell" on startup, and the fact that I had a total failure of the right cyl bank with multiple misfires back in December resulting in a ton of raw fuel being dumped into it.

Sgt. Schultz

Funny you ask, I was just yesterday wondering the same. I don't need them, but my curiousity was piqued as I backed into my garage and smelled them burning. Also while on way home w/ sunroof open, I could smell myself (um, car) which is odd.

So I figure they'll F the pooch down the road a ways and pondered what options existed.

I'd not run the el cheapo magnaflows on a car of this caliber - I ran their race "cats" (straight thru boxes) on my //S8 which I loved... but on cold start they would have a 'somewhat' audible chatter to the metal and sound kind of tin-y until they warmed up. I also wondered about their prospects of longevity, I expected them to rot off in a couple/few years honestly.



I bet there are some good 200cell race cat options out there, that would also free up restriction - I'll prob aim down that road when the time comes... hopefully not for a lonnnnnnnnng time 8-).

Good luck, keep us posted on what you do.

stockC43

Could be a abc damper starting to fail. They drone/vibrate/hum around 1200-1800 rpm. Easy test is to remove the drive belt and see if the noise goes away. After working for benz for over 8 years I've never personally seen a 275 cat fail. Not saying it cant though When it kills spark, it kills the injectors too so it "shouldn't" damage the cat

marktan

Hummm...where is the damper located. Noise sounds like it's coming from the passenger footwell (ish) area.

stockC43

That's exactly where it is located under the car. It will be a black ball shape attached to a aluminum block with 3 abc hoses and a pressure sensor attached to it. The ball just unscrews. Crack it loose slowly as it may be under pressure, let the pressure bleed off before fully unscrewing it Then just top off the abc system with pentosin chf11s

marktan

Awesome! Thanks man!! Anyone have a part number off hand?

stockC43

Should be 220 327 02 15 and you may need the seal ring 028 997 33 48. Not sure if it's included

marktan

Again, I really apprecaite that!
Any idea how "critical" this unit is? I can tolerate the soft drone for a little while, but if it's going to cause and subject me to total ABC failure, I'll deal with it in the next week. She has subject my wallet to much pain the last couple months: https://mbworld.org/forums/5168527-post11.html (add front brakes and rotors to the list as of this week) and a short break would be nice.