Can You Wash the Car Immediately After Driving on the Highway?
2 Answers
You should not wash the car immediately after driving on the highway; instead, wait for 15 to 20 minutes. This is because the brakes and engine are still in the cooling-down phase. If you wash the car right away, using cold water to rinse the brake discs may cause them to warp in mild cases or lead to brake system failure in severe cases, compromising driving safety. Here are some precautions to keep in mind when washing your car: Avoid prolonged rinsing: Simply rinse off the loose dust on the car's surface. For heavily soiled areas like the underbody guards, targeted high-pressure rinsing is acceptable. Maintain a proper distance: When using a car wash bay's water gun, ensure you do not stand too close to the car body. Keep a safe distance, and avoid directly spraying the engine area. Instead, hold the nozzle at an angle from above or below the car body. Wait for the engine to cool down: Washing the car or engine with cold water while the engine is still hot can cause significant damage. Avoid rough materials: Do not use rough towels or materials for wiping. Opt for soft cotton or polyester cloths to prevent scratches. Use dedicated cleaning agents: Ensure the cleaning agents you use are neither too alkaline nor too acidic, as they may corrode the surface. Use dedicated car wash solutions or dilute them to the appropriate concentration.
I've encountered this situation several times while repairing cars. After driving on the highway, the brake discs get so hot you could fry an egg on them. If you wash the car immediately and cold water is poured on them, the thermal expansion and contraction will definitely cause problems. Just last week, a Mercedes had to have its brake discs replaced because the owner hosed it down right after coming off the highway, causing them to warp. I recommend waiting half an hour before going to the car wash—just touch the wheel hub, and if it's not hot to the touch, it's fine. Also, remember to put a waterproof film over the air conditioning intake. High-temperature components can crack suddenly when exposed to cold water, and the car's paint or chrome parts might develop foggy spots. Especially in summer when temperatures are high, I've seen people rush to wash their cars only to find the hood's paint bubbling the next day.
