Spring is coming and I'm going to wash the grime off of the engine and under the hood on my 4.4. After 6 years of operation it's looking a little gritty. On past cars, I would spray it generously with Simple Green and hose it off. Has anyone done this and have any comments or suggestions I should consider?

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2013 X5 3.5i M Sport
2004 M3 cabriolet SMG