Can water leak from the drain hole in car even when ac is not on?

Yes, water can leak from the drain hole in a car even when the air conditioner is not on. The drain hole is designed to allow water to drain from the evaporator core, which is part of the air conditioning system. However, water can also collect in the drain pan under the evaporator core due to condensation from the outside air, or from rain or snow that seeps into the drain pan. If the drain pan is full, water can overflow and leak from the drain hole, even when the air conditioner is not on.

To prevent water from leaking from the drain hole, it is important to make sure that the drain pan is clean and free of debris, and that the drain hole is clear and unobstructed. If the drain hole is clogged, water can back up and overflow from the drain pan. You should also check the rubber seal around the drain hole to make sure that it is not cracked or damaged, which could also allow water to leak out.

If you are experiencing water leaking from the drain hole in your car, even when the air conditioner is not on, it is important to have it checked by a qualified mechanic to identify the source of the leak and have it repaired.