* So it looks like the overriding problem was water in the fuel(tank), coupled with a weak/intermittant spark due to poor connection(s) in the ignition primary circuit.
* Are you planning to drain the tank? If you have enough water to kill ignition (the engine cranked but didn't hit at all), a moisture additive might not be enough. Using a jumper at the socket for the fuel pump relay (to run the pumps w/o running the engine) you can empty the tank from the fuel inlet hose under the hood (disconnect the hose and connect it to a suitable drain into a refuse oil/fuel can). I think your car still had a stand-alone fuel pump relay (before MB got rid of the relay and incorporated that function into a control unit).
* Water through the combustion chamber, in my experience, doesn't automatically result in a damaged head gasket. Just add clean fuel (a fuel filter would be nice too), put in fresh plugs, and drive it. You'll know soon enough.

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ASE Master Tech
Quality Enterprises
Mercedes Svc. & Restoration
Sheridan, IN
317.769.3536