Is it serious if the car hood is left open in the rain?
3 Answers
It can have an impact. When it rains with the hood open, water can enter the air filter through the gaps between the hood and headlights of the car. If the drainage valve's function is reduced, rainwater may enter the engine through the intake pipe, causing the engine to fail to start. For minor cases, you can remove the distributor cap, dry it with a tissue, and reinstall it. If there is severe water ingress, it requires professional repair. More relevant information is as follows: 1. Note: When the car hood is closed, the engine's air filter provides partial waterproofing. A small amount of water entering the engine's intake pipe is blocked by the air filter, preventing direct entry into the engine. If the car stalls in water, ensure the engine intake does not inhale more water while prioritizing personal safety, and park in a safe location. 2. Handling stalling due to water ingress: Open the engine hood, remove the cylinder wires, take out the spark plugs, then start the engine. Water in the engine cylinders will be expelled through the spark plug holes. Hold the key in the start position for 5 seconds, release, wait 10 seconds, then start the engine for 5 seconds. Repeat this process three times to effectively drain all water from the engine.
That day I accidentally left the hood open overnight in the rain, and when I started the car, the AC wasn't cooling. The mechanic took it apart and found water droplets all around the ignition coils. He said electrical connectors in the engine bay are most vulnerable to water exposure, especially spots like the fuse box and alternator wiring ports. I spent half an hour wiping it down with a towel, but couldn't remove all the moisture trapped in the connector crevices. Eventually, we had to remove the ignition coils to air-dry them to fix the issue. My advice? If your engine gets wet, wipe it dry immediately—better yet, let the engine idle for 20 minutes to evaporate hidden moisture with heat. If you hear unusual noises at startup, shut it off and call a tow truck immediately. Forcing it to run could fry the ECU.
Last time after garage maintenance, I forgot to close the hood, and the community sprinkler system happened to turn on, giving it a thorough soaking. Experience tells me that in such situations, three key areas need checking: whether there's white crystalline buildup on the battery terminals, any signs of oxidation on wire harness connectors, and if there's water accumulation at the bottom of the air filter box. I used a household hair dryer on low heat for half an hour, focusing particularly on removing water droplets from the seams of the fuse box cover. Actually, short-term rain exposure isn't a big issue, but if it's continuous rainy season downpours for several days, the vacuum hose of the brake booster pump might accumulate water, affecting braking performance. Now I've developed a habit of walking around the car for a quick inspection before getting out.
