Can water enter the engine compartment?
3 Answers
Here are the reasons why you should not use water to clean inside the car engine compartment: 1. It can easily damage the generator, leading to failure. 2. If the engine is hot, the sudden cooling from water can cause significant harm due to thermal expansion and contraction. The engine block may crack under strong thermal shock. 3. There are many electrical wires in the engine compartment, and exposure to water can cause issues and accelerate wire aging. If you must use water, ensure critical components are waterproofed. It is recommended to use compressed air for cleaning instead. Precautions for water cleaning: 1. Cover the generator, distributor, brake fluid reservoir, etc., with cloth or plastic bags. 2. Only rinse after the engine has cooled down. Avoid using high-pressure water jets. 3. After rinsing, thoroughly dry the engine compartment with a clean cloth, especially the underside of the hood. 4. Do not directly spray water at the air intake or electrical connectors.
I've been driving for fifteen years and have repaired no less than a hundred engine hoods. Water getting into the engine compartment is actually quite common. A little water splashing in while driving in the rain or during car washes is completely fine—manufacturers design for water resistance. However, if the water level exceeds the height of the intake or you directly spray a high-pressure washer onto the fuse box and alternator, you're definitely asking for trouble. A short circuit can leave you stranded on the road in no time. Once, my neighbor parked without noticing a puddle on the ground, and the next day, smoke poured out upon starting. So, in short, don’t worry about water under normal use, but avoid prolonged submersion or deliberately spraying large amounts of water. After each wash, check the corners of the engine bay for standing water, especially around the battery.
As a DIY car washing enthusiast, I've researched engine bay waterproofing. In fact, there are dedicated drainage channels under the hood designed to direct rainwater along specific paths to the undercarriage. Electrical connectors mostly have rubber seals, and spark plugs are covered with dust caps, so minor water exposure causes no issues. However, two points require attention: aging vehicles may have cracked rubber components, making them prone to sensor malfunctions when wet; additionally, modified cars (like those with aftermarket HID ballasts) may have compromised waterproofing. I personally wash my engine bay weekly during car washes, carefully avoiding the ECU and air filter areas, then immediately using compressed air to dry electrical connectors - with zero issues over three years of this practice.
