I have noticed some detailers use different processes on cleaning an engine bay. Some procedures may be more controversial than others. I have been detailing my own cars and customers cars for about a year and a half now. I don’t clean the engine bay every wash. From my experience, it only needs to be cleaned once or twice a year. If it isn’t neglected, it only takes a few minutes to clean up. My process changes from car to car and especially the age of the car.
The process I use for most modern cars involves a pressure washer, an all-purpose cleaner (APC), and a few brushes. First, I take a look at the engine for anything that may need to be covered. Parts such as air intakes and battery terminals need to be covered with a towel. Next, wash off the engine, degrease with APC and agitate with brushes. In most modern engine bays, everything can get wet and the car will function okay. However, this is the most controversial process. Lots of people cringe at the fact of using a pressure washer on the engine. In my experience, I have found no issues with this. A more comfortable process some may use is hose water, all-purpose cleaner and brushes. On an older vehicle, such as my 1991 Jeep Wrangler, this is what I will do. Some older vehicles have a distributer cap, an air intake, and exposed wires or weak wire harnesses. These should not be pressure washed or hit with water in general. What I would do is be careful with the hose water and cover up these parts with a towel. The last process I may use involves only all-purpose cleaner, brushes and towels. This would be a dry engine bay cleaning (meaning no water involved). If an engine bay just needs a touch up, this works best. There is no need to use water.
After letting the water drip out or drying it off, I use a product to shine it up. Adams Polishes In & Out spray works well on plastics to leave a satin black finish. Another product I use is CarPro Perl diluted with water 3:1. I spray this on the entire engine bay and let it sit, this also leaves a satin black finish.
I will include some before and after pictures of an engine bay I did on a truck. My question to you is, what is your engine bay cleaning process? Do you use a combination of what I do or do you use an entirely different process? Thanks for reading!