I keep getting po 455 ( large emmission leak) on my 1997 e_420-w-124. Where should i look?????

Loose gas cap? Does the purge valve work? Could be a few different things.

I'd start by replacing the seal on the gas cap; that's a few bucks at the dealer. From there clean the purge valve and make sure the lines to it (as well as the vacuum line and connections) are sound and secure. From there remove the RR wheel and pop the wheelwell and start checking out the evap canister, lines and evap valve atop the canister.

If you're in the US with a windows PC you can register for the EPC for free and then see a rough diagram of the evap recovery system. Anything in it is a potential suspect, but start small and easy and progress from there (as outlined above).

Good luck.

Think again! They were only made until august 1995.

__________________
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300E 4Matic '88
240D '83
280SE '77
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The most complex systems can fail in the simplest way.
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i don't believe in the lord! He's never bought me a Mercedes Benz.

I'm operating under the presumption he has the W210 "orphan" car (E420 only one year, 1997, in the W210 line) and mistakenly guessed at the chassis designation.

Thanks Guys I dont know where I got 124??????? I replaced gas cap, Where is purge valve????

It's in front of the ABS plumbing on the driver's side, it has the letters "MOT" on top of it.

Thanks CK I found a hose off. Checks in the mail....