A clean engine bay makes leaks visible, keeps connectors and labels readable, and photographs well when you sell. But the horror stories are real: a pressure washer aimed into a modern engine bay can force water past connector seals, into the alternator, or into a coil pack, and the misfire may only show up days later as corrosion sets in. The professional method is low pressure or none at all — degreaser, agitation with brushes, a gentle rinse or steam, and compressed air to dry — with the battery terminals, fuse box, alternator, intake inlet and any exposed ECU covered before a drop of anything is sprayed.
If a mobile detailer proposes to pressure-wash your engine bay in your building's car park, decline. Beyond the electrical risk, most Dubai and Abu Dhabi tower car parks prohibit runoff-producing work, and degreaser runoff is exactly what building management fines residents for. A steam-based bay clean, or doing that one item at a workshop, sidesteps both problems.