I'd love to know your process for cleaning the engine bay
OK. Here you go. Start with the engine cold. I always worry about thermal shock cracking a manifold or something.
Spray everything down really well with full strength Simple Green including under the wheel wells, front end parts, exposed parts of the frame & the underside of the hood & let it sit for 20 or 30 minutes. If you’ve got a lot of grease, oil or other build-up you can agitate it with some kind of brush. Then rinse it with a light, low pressure spray from a garden hose; NOT a pressure washer. I never cover anything, but I try to avoid spraying water directly in electrical components or down the air intake. Look things over & spot clean any remaining dirty spots or even repeat the entire process.
At this point I like to start the engine just to make sure that I haven’t messed up anything. It’s never failed to start & I’ve never had any problems, but this step gives me some peace of mind. Close the hood to hold in some heat & let it run for a few minutes or drive it around a bit to dry things out. Take a look & spot clean anything you might have missed & dry off the excess water with an old towel.
Let it sit long enough to dry completely (usually over night) & take a look. Now that it’s dry it will be easier to see any spots that you might have missed. Go ahead & take care of that.
When you are satisfied that everything is clean, spray a fine mist of some kind of protectant. I like Formula 303 Aerospace Protectant, but Armor All or something else would also work. You don’t need to wipe it down. It will dry to a nice shine on its own. Don’t forget to treat your front end parts, exposed parts of the frame & such, but not the understood the hood. If the paint is good you will want to wax that.
That’s it! It’s not that hard if you don’t let it go too far & do regular cleaning.
Have fun!