Is Your Car Leaking Antifreeze When Parked? [Causes & Fixes]

Cars have hundreds and thousands of components. Most of these small and internal components are metal. These parts when they get in contact produce heat because of the friction. Coolants control the temperature of the engine for efficient performance. But on winter days, the coolant and also the water in the reservoir gets frozen and cannot be used. Antifreeze must be filled with coolant to avoid freezing. If the car is leaking antifreeze and the driver haven’t noticed it, it could cause engine stall while driving. Check out what are the common causes of the car leaking antifreeze when parked or while driving and learn how to solve them.

What Is Antifreeze?

In olden days, water is filled in a reservoir and is pumped around the engine to regulate the temperature. The dial in the car shows the temperature of the engine. It is evident that water freeze in winter days. To overcome the problem, antifreeze coolants are used in the places of water. The chemical formula mixed with water does not allow the water to freeze but also absorbs more heat from the engine. So the coolant can be used all around the year. It has also been proven effective than cars using water as a coolant. Nowadays, water for your windshield also has antifreeze so no more frozen waters in the car cooling system.

Why Is My Car Leaking Antifreeze But Not Overheating?

Cars have gaskets, and that wears out over some time and causes leakage. It applies to all the components that get in contact with lubricants and fluids. If your car leaking antifreeze when parked, there could be a leakage in the system. It could be because of either bad radiator cap or internal coolant leak or external leak. You have to find the cause of leakage to solve the issue.

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1. Radiator Cap Leak

If the cap is struck, it blocks the flow of coolant. It increases the pressure near the lid and pops it open over some time. A broken radiator cap could cause leakage because when a car is stopped after a drive, the coolant flows back and rises again, which causes overflow. It makes your car leaking antifreeze when parked.

2.Internal Coolant Leak

The antifreeze coolant flows internally through the engine to pick up heat. If there is an internal leak of coolant inside the engine, it either mixes up with the oil or burns with air mixture as exhaust. This spoiled oil will damage your engine over time. In case of an internal coolant leak, you could never notice your antifreeze leaking at the bottom because it will never come out.

3.External Coolant Leak

The radiator hoses are the cause of external coolant leak. The tubes are made of rubber, and it degrades over time. Small damage to the hoses will cause leakage. You can notice the coolant pouring out from the bottom of the car when parked or even while driving.

How To Fix A Car Leaking Antifreeze?

Smaller issues and faults in a car can be solved by ourself in the garage. But you should have all the necessary tools and equipment to perform the task. If there are any replacements, then get standard spare parts and don’t try to reuse the old parts.

1. Fix-It Yourself

If your car leaking antifreeze when parked because of a radiator cap, then you can see stains of the coolant around the lid and at the bottom of the vehicle. To fix it, first, empty the coolant reservoir. Then remove the radiator cap and replacement it with the new one. Now, fill the antifreeze coolant and leave your car parked. Check it the next day for leaks. If there are no stains, then your problem is fixed.

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2. Hire A Mechanic

Both internal and external coolant leakage can be solved by a professional. Check your coolant level in the reservoir for two days because internal leakage never leaves any stain marks or puddle under the car. If you notice a significant difference in the tank, then there could be an internal coolant leakage. Leave your car to the mechanic, so that they can resolve the problems by changing internal flow lines and change the oil. After service, fill the reservoir and check if your car leaking antifreeze again.

If the radiator caps are good, but you still find leakage and puddle of coolant under your car, then it could be external leakage. The radiator system has complicated connections, so it better to hire a mechanic. He will replace the damaged hoses with new hoses at required places. Refill the coolant reservoir to check if your car leaking antifreeze when parked. If there is no sign of strain, then your problem has been resolved.

How Much Does It Cost To Fix An Antifreeze Leak?

The radiator caps are not much expensive. Also, you don’t need any labour as you can fix it yourself. A radiator cap will cost less than $25, and you can get it in an auto parts store. Also, the antifreeze coolant varies from $100 to $150 based on the quality and type of fluid your car requires.

A radiator hose costs around $35 to $65, and you have to pay labour charges for the mechanic. It varies based on the work done by the mechanic. It is not much expensive work, and it fixes your problem for some more time.

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An internal coolant leak could damage the head gaskets in the engine, and at worst it could damage your radiator. A radiator replacement costs around $300 to $400 despite labour charges. It is quite an expensive work. The replacement of the head gasket is more uncomplicated than replacing your radiator. After fixing the issues, refill the coolant reservoir and leave your car parked overnight. Check if your car leaking antifreeze when parked, if not, then there is no leakage in your car.


Every complicated component in the car requires much care and service over time to avoid these kinds of issues. Also, use the lubricants and coolants that are suggested to your vehicle, and replace it over time. Have a scheduled service of your car to avoid significant problems and replacements. If your car is leaking antifreeze, then don’t panic. Check for the cause of leakage and try to repair it immediately.

It will avoid the upcoming issues with your car. If you ignore such problems, it will cost you more than usual to fix it again. I believe this article will give you an idea about how to fix the coolant leaking from the bottom of the car when parked.

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