What are the disadvantages of washing an engine with water?

[McMadeline]

There are no disadvantages to washing the engine compartment with a water gun. Additional information on engine cleaning is as follows: 1. You can use a water gun to clean: However, the fuse box must not be washed and can be wrapped in plastic film. After cleaning, it is necessary to immediately use a high-pressure water gun to dry it, otherwise water ingress into the wire harness connectors can cause vehicle malfunctions. 2. If the engine does not leak oil: If there is only dust and dirt on the surface, then it is not necessary to clean it, and there is no harm to the engine. 3. If the engine leaks oil: It is best to clean it regularly. A common engine oil leak is from the valve cover gasket. The leaked oil will adhere to the entire engine. Engine oil easily attracts dust, and the mixture of dust, dirt, and oil, when baked by the engine's high temperature, will form a thick layer of sludge. 4. Sludge is corrosive: If it gets on the engine wiring or rubber hoses, it can corrode these components, accelerating the aging of the wiring and rubber. Therefore, it is best to clean it. It is recommended to clean the engine compartment at a professional shop, as they have specialized cleaning agents for better cleaning results. They know which areas can and cannot be washed, as they are professionals.

[LaElias]

Last year I bought a used car and impulsively washed the engine bay directly with a hose, which turned out to be a huge mistake. The next day when starting the car, it shook violently. The mechanic said water had entered the ignition coils, causing a short circuit. It cost nearly two thousand yuan to replace the parts. Even worse, the hidden wire connectors started rusting as soon as they got wet, leading to poor contact over time and affecting the entire electrical system. I later found out online that modern car engine bays are packed with electronic components like ECUs and sensors, which can easily corrode or get damaged by high-pressure water. Next time, I'll use compressed air for cleaning—simple and hassle-free. For regular maintenance, I'll just wipe off dust with a dry cloth to avoid major repairs. Remember, washing the engine with water might feel satisfying in the moment, but the repair bills are unbearable.

[DelJade]

Last month, I just got my driver's license. While washing my car, I noticed the engine was very dirty, so I tried to clean it with a water spray gun. A few days later, when I drove out, the dashboard lights started flashing randomly, and the car suddenly stalled on the road. After towing it to the repair shop, the mechanic checked and said water had seeped into the relay box, causing a short circuit, and even burned out a fuse. The repair cost over 500 yuan. I later realized that washing the engine with water might look cool, but it's too risky. Especially for new cars, water can damage the smart control systems. Now I carefully clean with a soft brush and damp cloth, never letting water near the electrical parts. Spending more time on maintenance is better than breaking down. Developing good habits makes driving more reassuring.

[LeCalvin]

Having worked in a repair shop for ten years, I often see customers bringing in their cars for maintenance after washing the engine with water. The main issues include short circuits in the ignition system, water reaching the spark plugs or sensors, causing difficulty in starting. Over time, oxidation of the wiring can also lead to intermittent faults, such as flickering lights. Another major problem is water residue trapped in engine crevices, leading to part corrosion. I recommend using specialized cleaning sprays for wiping instead of hosing down with water. For daily maintenance, using a low-pressure air pump to blow away dust is the safest option to avoid costly repairs.