It’s not unusual to see a puddle or stain underneath your car. Most people, in fact, see a puddle and just ignore it, thinking it’s nothing to worry about.

Sometimes it is nothing to worry about – but it’s important that you know what puddles or stains are ok, and which ones need attention.

Is it normal for a car to leak water?

One of the most common causes of a puddle underneath your vehicle is that it’s leaking water. How do you know if it’s water?

You can start by having a read of this helpful Guide to Identifying and Addressing Car Fluid Leaks.

Most of the time, it’s perfectly normal for your car to leak a small amount of water, and that’s nothing to worry about.

But let’s take a look at how to check what is a normal amount and what might be causing your car to leak water.

How to check a car’s water level

Water plays an important role in your car. Water circulates around the engine to keep it cool, so without enough water, there is the risk that your car will overheat. This, in turn, can cause serious engine damage.

It’s important that your car’s engine is cold when you check your car’s water level. Open the bonnet and secure it, then locate the coolant reservoir. If you don’t know where this is, refer to the manufacturer’s manual.

Next, check that the water level is sitting somewhere between the minimum and maximum levels marked (these levels may be marked on some vehicles as “low” and “high”). It’s pretty straightforward, but if you need any help, just get in touch with the friendly team at Mt Roskill Collision Centre.

Car water tank leaking

If your water reservoir is leaking, there may be a problem with one or more of the connecting parts. Often water leaks are due to cracked or worn radiator hoses. Look for damage or holes to determine if that’s the reason.

A radiator cap may also be the cause of a water leak. Check that the cap and seal are intact, that there isn’t any damage, and that the cap is screwed on correctly.

There may also be corrosion on the water tank itself, which will cause water to leak from your car.

How to find a water leak in a car

It may seem obvious, but first check that the leak is indeed coming from your car. Move your car to another clean, dry parking spot and wait a few hours. Then check again for puddles.

Next, take a torch and have a look under your car. Can you see any obvious dripping or leaking? The other way to do this is to slide a sheet of white paper under your car where you suspect there is a leak to confirm whether or not any water (or other fluid) is dripping.

Don’t worry if you don’t know exactly what part of the car the leak is coming from. If you give us a call and describe the approximate location (front, rear, right, left, etc) we can tell you what to do next.

Water leakage from a car’s air conditioning

Your car’s air conditioning system produces condensation, which collects in a drip tray below the evaporator. This tray then drains through a small tube under the car.

If you’ve had your air conditioning system running on a hot day, you’ll likely see some water under your car. The water should be clear and odourless. If the water has a colour to it (e.g. green, red, pink, blue) or it has a chemical smell, it could be caused by something else that needs attention. There may be coolant in the water, which is a sign of a coolant leak that needs fixing. 

If the air con system is actually leaking a fair amount of water, you may actually have a more serious issue like a blown gasket or a blockage between the cylinder head and the engine. We suggest you stop using the AC and bring your vehicle in to be checked out.

Water leaking from your car when the heater is on 

We’ve seen that it’s normal for a small amount of water to “leak” from your car when the air conditioning is used. But if your car is leaking water when the heater is on, that may or may not be a different issue altogether.

A small water leak could also be condensation from the heating or cooling system.

An excessive amount of water, however, may be due to some other common cause of a water leak when the heater is on, including:

  • Clogged evaporator drain
  • Faulty seal
  • Leaking evaporator core
  • Blown cylinder head gasket
  • Damaged piston rings
  • Faulty EGR cooler

There are a number of reasons why your car may be leaking water. Don’t try to fix any of these issues yourself – bring your car into the professionals.

Water leaks from a car when it rains 

Cars are designed and built to be waterproof. So if your car is leaking when it rains, water may be getting in past the weatherstripping. These are the black rubber seals that surround your car’s glass surfaces (windows, windscreen, sunroof).

If your car is old or hasn’t been looked after properly, this rubber may perish, causing water to seep in. Often, these rubber strips can be replaced if needed. If you have a sunroof, occasionally, the water seeping into the car may be the result of leaves or debris getting stuck in the sunroof tray, preventing it from closing properly.

If you do suspect your car is leaking water – or any other fluid – don’t panic. Review the steps above and in our Guide to Identifying and Addressing Car Fluid Leaks.

Then feel free to get in touch with us. We can discuss the possible issues with you and give you advice on what to do next.

Call us on 0800 227 762 or email [email protected] for professional and friendly car servicing advice.

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