What are you adding? If it's antifreeze, it is colored, usually green, but sometimes red, orange or yellow. If you've been adding straight water, you might be seeing the results of that leak. In that case, look for the wet areas on the engine and follow that up to the highest point. Having to add every four or five days is a pretty bad leak and is only going to get worse.
I told you of the most common cause of finding clear water dripping onto the ground. That is from running the AC, and is an important part of that system. AC systems are only expected to lower air temperature by around 20 degrees. The real comfort comes from removing the humidity. It condenses on the cold evaporator in the dash, collects in a tray, then flows out and onto the ground, just inside the right front tire. When you don't see that dripping water is when you have a problem with that system. It's not uncommon for the drain tube to become plugged with leaves and debris. That results in a sloshing sound in the dash and water splashing on the front passengers' feet.
If you've been adding only water to the cooling system for some time, there is likely no colored antifreeze in there now. In that case you would see only clear water leaking out. If the leakage is too slow to find, a common way to approach this is to add a small bottle of dye. Wait long enough for some leakage to occur, whether that's an hour or a day, then search with a black light. The dye will show up as a bright yellow stain that you can follow back to the source of the leak.
Most auto parts stores rent or borrow specialty tools including that black light. In my city, they make you buy the tool, then you get a full refund when you return it. If you choose to keep a tool, you still return it, then they give or order you a brand new one.
Another method is to use a cooling system pressure tester. That lets you build pressure in the system without having to get the engine hot. It's no fun crawling around on a hot engine trying to find a leak. The problem with this method is it may not produce the conditions under which the leak occurs. For example, some leaks, such as a water pump rubber lip seal can seal better and leak less when under pressure, then leak later when that pressure goes down. Some leaks are temperature-related. This would be typical of a cracked cylinder head. The metal expands when it gets hot. That expansion can cause a crack to close up and leak less, or open up and leak faster. Often we have to experiment with the pressure tester to find the best condition to make the leak occur.
I've had good luck with the dye and black light, but it isn't always a practical choice when you have to make the car owner come back a day later. It's also easier to use this method when you have the vehicle on a hoist.
Jul 3, 2026 at 7:51 PM