Time: 10-15 min

Difficulty: easy

Cost: $0-20

Why Clean

When you have a clean, well-maintained vehicle, you're more likely to appreciate and invest in it. A clean engine compartment makes maintenance easier to perform and problems easier to find. It also communicates pride of ownership and higher overall vehicle health. Clean parts also last longer as salt, acidic buildup, grime, and other corrosive chemicals are removed.

Is it Bad to Spray the Engine?

The engine is designed to keep water out and vital fluids in.  Electrical components are similarly protected with watertight connections, gaskets, and O-rings.  The exposed battery and alternator are low voltage systems and will not arc or spark when exposed to water. Driving through puddles or spraying the engine compartment with water are expected and planned-for occurrences.

Possible Exceptions

Water resistance or waterproof? Deep submersion from flood or fording can allow water to be drawn or soaked-in through the air intake system. It can also find it's way into fuse boxes or other electrical components that are covered, but not sealed. While this might not affect the electrical system immediately, it may birth gremlins as unescaped water pools and corrodes.

Another possibility, though far less likely on modern distributorless ignition systems, is a misfire. Very rarely, when hosing an engine, water might get passed a spark plug tube seal. In this case, the electrical path to ground may prove easier through a temporary water track as compared to the spark plug gap within the high pressures of a cylinder. Should this happen, the engine will experience a misfire on that cylinder and the "Check Engine" light will illuminate. A code reader will tell you which spark plug tube seal is to blame. To resolve the issue, remove the coil (not the plug) and dry out the boot and spark plug hole with compressed air. You're back in business.

Watch the video below to see the engine wash on a 2019-2024 GMC Sierra. It'll look the same on any GM V8 (Silverado, Yukon, Tahoe, Suburban).