Help with BMW 330i engine cleaning

I have recently acquired a 2004 330i. The engine is quite dirty as you can imagine in a 12 year old car. I know the safety of engine bay cleaning has been discussed over and over again but when I opened the hood and was about to rinse everything down, I could see a lot of the covers typically found in automotive wiring end with a short distance of individual wires that plug into their respective harnesses (if that makes any sense)

I chickened out and ended up not cleaning the engine bay out of fear of wetting the harnesses too much.

Does anybody have experience detailing the engine bay of an E46 (99-2005) BMW 3 series and what precautions should I take?

 

Any aftermarket mods on the car in that engine bay compartment, HIDs, cold air intakes etc?

 

As a general rule I spray liberally with your APC or choice. Let dwell for a while. Use some brushes to agitate any heavy gunked up areas and then I lightly spray the engine compartment down with water. I DO NOT use a pressure washer or full blast stream from the hose. I will also attempt to keep the alternator as dry as possible. Remember: most engine bays/areas/pieces are made to take some moisture/water, but not a huge deluge of water.

Spray it,down, agitate it, spray it off. Apply the dressing/lsp of your choice. You will be fine!

We will, or course, need some before and after pictures!

 

I always cover the alternator with a plastic bag and never use the pressure washer. I spray APC and let it dwell before I scrub. You shouldn't need anything stronger than a garden hose at normal pressure. Try to avoid soaking the fuse box and other electrical components. Apply just enough water to remove the APC.