Engine bay wash

[JCT-DK]

Would it be safe to wash the engine bay?

What should I pay attention to?

I consider spraying a solution of water and degreaser on all of the bay parts and rinse with a water hose.

Would it be safe to rinse the whole bay? What about the electric motor?

After that adding protective solution of water and vinyl makeup on all plastic and rubber parts.

Thanks!

[anchorman]

All I will say is that when travelling in driving rain, it isn’t dry in the engine compartment.  

[TonyHSD]

No problems washing your engine bay, it is also a good idea. Very important to cover air intake hole with plastic bag or towel, no water should get in. Check air filter for being dry before attempt to start the car. You can use chemicals, degreaser etc and soft brush . When rinse with a hose you can use spray pattern on your hose adapter and keep 20cm from anywhere you wash. Same applies if you use a jet wash, jet wash can cut through wires and damage some sensors or wire harness, that’s all you need to be careful. All electronics are water tight, no worries there. As Don said , when driving through the rain all under the bonnet gets soaked in water . 
 

[JCT-DK]

Great thanks Tony.

What about the electric unit (motor). Is it wrapped in an aluminum box and can I just clean and rinse it as well?

Should I pay attention to the two orange harnesses on the back?

[TonyHSD]

15 hours ago, JCT-DK said:

Great thanks Tony.

What about the electric unit (motor). Is it wrapped in an aluminum box and can I just clean and rinse it as well?

Should I pay attention to the two orange harnesses on the back?

These are well protected, no worries about them. Just use a good quality valeting products and avoid using any strong acid, just a regular tfr mixture or engine bay degreaser and soft brush. 
Some tips: 
best to do it in a sunny day but work under shade or shadow, start the car and let the engine warm up a bit 5 min work max and then wash it.
After you complete your wash keep bonnet open and start drying with microfibre towel. If you have a wet vacuum you can suck water from all wire harnesses connectors carefully, and any places water may seats, around air filter housing, coils, etc. if no wet vac then you can use something like disperse air under pressure just to blow the water at these places. Wipe dry all surfaces that holds water. Leave it open for few hours to air dry. Now if you want you can treat all metal parts that has corrosion with wd-40 silicone spray for those who touch rubber or plastic. Just sorry over little bit and wipe any excess. You can treat the rubber bonnet seal with the same spray and the hinges. At the end apply some oil on the lock mechanism or at least some wd-40 classic spray and some grease on the lock hook to keep everything in good shape. Job done. 👌

[bathtub tom]

When, on the rare occasion, I wash the car, I use a soft brush on the end of a hose and give the engine a quick wash. I never use any oil or grease products under the bonnet in case they remain sticky and collect dirt. I then give it a quick run round the block, using the brakes to deter rust.

[JCT-DK]

Great thanks Tony.

I look forward getting the job done. 

[Guest]

Personally, I cover/protect the alternator with clingfilm. Other than that let it rip, in moderation.

Not a Hybrid though.

That's when inclined to clean under there.

[JCT-DK]

Yes I am having a hybrid so safe to wash the entire bay.