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.
Timing matters in this climate specifically. Spraying cold water across an engine that has been heat-soaked to UAE summer temperatures thermally shocks plastics and can crack a hot exhaust manifold coating; the job should be done on a cool engine, which in July effectively means first thing in the morning or after hours parked in shade. Afterwards, a water-based dressing on the plastics restores the factory look — solvent and silicone dressings in a bay that runs at high temperature just bake off and smoke.