Lefix

Hey guys, I've had a exhaust rattle for about 2 months now, about 3 weeks ago it got louder and rattled more often, I took it to an exhaust shop and they think it is the passenger side secondary catalytic converter. They told me the only way is to replace the entire catalytic converter, which the part alone from mercedes costs $1350.. Plus I'm in CA so they told me I can't get aftermarket parts...

This morning I started up the car and the check engine light started flashing. I turned the car off right away and then started it up then it became a solid check engine light. The car sounded fine and idle smooth so I drove to work (~10 miles). After work I drove back home, car still felt normal.

My thought is this: The passenger side cat is melted and needs to be replaced/repaired, the oxygen sensor is showing higher CO2 reading and triggered the check engine light. HOWEVER, i thought there isn't a sensor AFTER the secondary cat so even if it is melted, it won't trigger a code?

Please help because I don't want this to turn into a bigger problem..

Thank you!

vettdvr

There is 4 o2 sensors. If you have a plugged cat change it. You will have nothing but more problems if it isn't repaired.

Lefix

Do you guys think it is a plugged cat?

I've been away on travel for work and haven't been able to get my car looked at yet.

Any more inputs?

AMGAffalterbach

If it is a rattle it could also be a collapsed or partially collapsed cat but unless you have someone look at it all we can do is guess - and my best guess is that it is a damaged or plugged cat as it has O2 sensors in the primary (but not secondary) catalytic converter.

wipster

I need to get the converters on both sides replaced on my '03 E320 (~130K miles) per the local dealership. One is apparently leaking catalyst (?) and the other has a hole in it. My check engine light just came on around 100 miles ago (about 300 miles after they made the diagnosis). They quoted me ~ $2,400 just for the converters and checking aftermarket I can get Walkers for under $600 for each side and Eastern Catalytics for around $400 each. I used to sell Walker exhaust long ago in my parts man days and it is a brand that I trust... I'm not familiar with Eastern (BTW, NAPA's exhaust line is made by Walker and rebadged).

Have any of you gentlemen or ladies used any aftermarket converters? If so, can you share your experience? I'm not in CA, so no problem with legality here in WA. I just find it awfully hard to justify twice the price for these, so your thoughts will be greatly appreciated!

Peace and Long Life
\\ //
-( )

homeofstone

I used after market direct fit converters/with pipes on my Chevy Suburban 4 years ago and they are still performing like OEM. I purchased mine through Advance auto parts. Sorry I can't speak to Mercedes aftermarket converter parts since I have not had that problem on my Mercedes.

wipster

Thanks for the swift reply Home. I'm definitely leaning towards aftermarket. BTW, sharp looking E500!

homeofstone

Thanks, Picture is of my 2007 E350. My E500 is a 2005 with sport pkg. and with 127,000 miles on it. Neither has the power or is as reliable as my Hyundai Genesis 4.6 V8.

bernard farquar

There are no aftermarket cats for the w211, there are some listed for 2003, but those are for the w210 that was sold as a 2003. I had this issue, with a secondary cat plugging, it was throwing misfire codes, rattling etc,, by the time I got it to the dealer (the only parts source for it) it had spit out the insides of the cat. since there are only four O2 sensors, once the blockage was cleared, all systems read normal. So now I have three cats, and I didnt spend 1600 bucks plus install on the cats.

wipster

My apologies Home, the 350 looks great as well! Interesting about the Hyundai... I knew they looked good, but that's wild about the power (the reliability doesn't surprise me). The Koreans catch up fast, they've learned their lessons well from the Japanese, as I hear they have surpassed them also... I wonder what they will name their luxury lines?

wipster

Mr. Farquar, that explains the remarks I was getting from the Dealership, asking me to let them know how the aftermarket units worked out. It also explains why the 2003 looks so much different than the 2004 aftermarket units. I take it the 2004 wasn't the same as the 2003 W211? Or did you not bother to replace them once the insides had all gone bye bye and the blockage had cleared? Did the blockage disappear by itself (was it caused by the leaking catalyst) or did you or the dealer have to clear it? After the blockage was gone, I take it that the check engine just didn't come on any more, since the issue no longer existed.

Sorry for all the questions, but your answer is just what I was looking for and I really appreciate the swift reply. Now that the one catalyst is basically not there any more, have you noticed any difference in the way it runs and/or mileage? I would think not, but I had to ask.

Thanks my friend! I anxiously await your response!

homeofstone

Yep my 4.6 V8 Genesis has 385 hp 0-60mph 5.5 seconds. The Genesis R-spec 429hp 0-60 in 4.8 seconds and corners like its on rails. The Mercedes still rides better and handles better. Good luck with the cats.

bernard farquar

the 2003 w211 is the same as the 2004 w211, the issue is that the only aftermarket ones I found were for the last w210 wagon, sold as a 2003.

Once I got the car to the dealer, the right rear cat had spit out it's guts, and I elected to accept that as the new reality. I have had no issues since it cleared the blockage, I only had issues while it had materiel inside to cause a blockage

AMGAffalterbach

Time to straightpipe

wipster

Well, it sounds like that's what you end up with regardless. I believe I'll follow Mr. Farquar's advice to the chagrin of the dealer and blow her clean out and continue to run that way... straight pipin' baby. The CE indicator is no longer on, so maybe I've blown it all out of one side at least. Doesn't seem to impact the way it runs or mileage, I don't hear a rattle, and there is no emissions testing required in our community (yet), so no worries, eh?

Thanks for your input and advice everyone!

\\ //
-( )

AMGAffalterbach

If you have no emissions testing to abide by then get rid of it!! Good plan, even without it these engines are pretty clean burning compared to some