I talked to a cousin who owns an MB repair shop in Lancaster, CA. When I washed the engine, he says that I ruined a temp switch that controls the auxiliary fan. This is a common problem. The temp switch has to be sealed with silicon RTV to protect it from water.

I trust the diagnosis not only because he is my cousin but also because as soon as I spoke of washing the engine, he immediately told me that my auxiliary fan continuously runs and that the AC is not blowing cold. I asked how he knew that. He says it is a common problem.

He will be ordering the part for me. I will post what it is exactly called including part number.

Another caveat when cleaning the engine is to keep water away from the air filter and duct to the engine. Water in the engine is quick way to ruin a good engine.

Hope this helps.