I fell in love with Mercedes after a family friend dropped by in a v12 W140 many years ago. Yesterday I had the great pleasure of buying a w124 E320--without ASR
Today I went to run some errands and wash the car before going over it with a clay bar and, upon parking the car, was surprised to hear a very loud mechanical chattering from just behind/below the passenger-side dash that did not stop until I disconnected the battery. By this point, a wisp of white smoke had begun to issue forth from the EGR valve mounted on the passenger-side back of the engine ('Pierburg 7 2 0850 82 06T144'). There was also a noise coming from the area around the exhaust manifold; a repetitive ticking around 5 times a second. Every time I reconnect the battery, these noises start up again--and it doesn't sound like it is coming from the EGR
This only happens when the car is off, and will go on indefinitely (I let it do this for nearly 7 minutes before disconnecting the battery a second time--this time without seeing anything from the EGR). When running, no problems. No codes, either.
I've been through the forums, the E-class owner's bible, and Google, looking for what this problem could be--which is accompanied by the smell of gas when under hard-ish throttle.
This is my college car and, under local "buyer's remorse" laws, I have 24 hours from purchase to return for a refund, which means I have until the end of today.
I got the car with a spotty history but a clean PPI (and 251,000 miles).
(Reposted in W124 forum as well)