Work · under the hood
Clean, not wet.
A finished engine bay should look like a well-kept machine: matte plastics, clean painted surfaces, dry seams. The glossy, dripping look people associate with this job is a dressing sprayed over everything, and it collects dust for a month and then looks worse than when it started.
Clean, not wet
Matte plastics, clean painted surfaces, dry seams. The glossy dripping look is a dressing, and it collects dust for a month.
The rules that keep it safe
- Cold engine. Never on a hot one. Cold water on hot metal and hot plastic causes warping and cracking, and cleaners flash off a hot surface before they can work and stain what they land on. If the car has just been driven, it waits.
- Cover what does not want water. The alternator, the intake and any exposed connectors or modules. Modern bays are far better sealed than they used to be, but “far better” is not an argument for aiming a lance at a fuse box.
- Low pressure, always. A gentle flow rinses. A pressure washer forces water past seals and behind covers, and the fault it causes turns up three days later as an intermittent electrical problem that nobody connects back to a wash.
- Degreaser, dwell, agitate. A citrus or all-purpose cleaner diluted appropriately, given time to work, then brushes — long soft ones for the tight runs, a detailing brush for the edges of covers, a stiffer one for the wheel-arch liner side of the bay.
- Blow it dry. Compressed air or a blower through every seam, cover edge and connector boot, so nothing sits in a channel and corrodes quietly for a year.
Dressing, done with restraint
A water-based matte dressing on plastics and hoses, applied to an applicator and wiped on rather than sprayed across the bay. It restores color to sun-faded covers without leaving a film. Silicone-heavy shine products are avoided: they sling off hot components, they catch dust immediately, and they can transfer to the underside of the hood insulation where they are almost impossible to get out.
What this is actually for
Two reasons, and neither is showing off. First, a clean bay is one you can actually inspect — a fresh oil weep or a coolant seep is obvious on clean paint and invisible under twelve years of grime. Second, when you sell the car, a tidy engine bay reads as maintenance history in a way no folder of receipts quite manages.
What we ask before starting. Whether the car has any known electrical faults, whether anything has been modified or added under the hood, and whether there is an active leak. A bay that is leaking oil should be repaired and then cleaned, in that order, because cleaning it first only hides the evidence a mechanic needs to find the source.