bingoldsby

...which I can hear only with the window rolled down and also only when driving very slowly and when decellerating - in the 5 to 10 mph range. This seems new, but I've only had the car, a 2000 E320 with 94,000 miles, for about three months and to which I have put on 4,000 of the miles.

I've read of the sound of "marbles" here, and on another board, and that's what it reminds me of - I think - from which the subject of catalytic converters and exhaust is discussed. I don't have any check-engine light, and the engine seems to be running just fine.

Anyone got any ideas, before I take it in?

Thanks,

Brian - Yakima, WA
2000 E320

E-Klasse

The media inside one or both of the catalytic converters breaks up and sounds like rocks in a tin can. The exhaust still passes over it for it to work so you don't get a CEL. The cats will have to be replaced.

bingoldsby

Thank you ______,

That's what I was thinking.

I've also read here and there about independant muffler shops doing a replacement - welding in whatever will fit, and that being a good and much less expensive way to go.

Any comments or instructions about that?? Such as... should I try to find and purchase cats on-line and take them to the muffler shop for installation?

Thanks again,

Brian

livetodrive

I had the same problem. Actually, it was my wife who noticed the noise with the window down. She took it into M-B and went for a test drive with the service advisor. Once he heard it he kept the car. It was the auxiliary fan belt (belt for the auxiliary fans). There were no malfunction indications on the dash.

bingoldsby

Hmmm.

Well that complicates the diagnosis a little. I do believe that I heard the rattle when I had come to a stop after hearing it while driving slow the other day. I should have gotten out then and tried to find it. I'll see if I can duplicate that situation and perhaps I can pinpoint it.

If it's an aux. fan belt, that seems like it would be quicker and less expensive to fix for sure.

Thanks for the suggestion and heads-up.

Brian

E-Klasse

When mine went bad I had a pair of Magnaflo high flow cats welded in for a lot less than the stock price. Check with a muffler shop in your area.

lexrex

Has anyone ever tried DEC catalytic converters? I've read elsewhere -- mainly on BMW forums -- that they're pretty good. They make a direct fit for the E-class. Auto Parts Warehouse sells them for $362 each.

lexrex

Has anyone had any trouble passing emissions inspection after installing an aftermarket cat?