As an Amazon Associate I earn from qualifying purchases.

Can You Drive a Car With Just Water in the Radiator?


Imagine you are on a long drive with your loved one, and suddenly you realize you have no more coolant. There is no automotive shop, and your car’s engine health is also vital for you. 

Now the question is: can you drive a car with just water in the radiator

Yes, you can drive your car with water in your radiator. In case of an emergency, it can be possible. But it is not a long-term solution.  While you may drive the car for a short time without coolant, your engine will be less protected. 

It’s not recommended to run your vehicle with just water in the radiator, according to Hammer and Coop. If there is an emergency case, then you can try it. 

Let’s get more insight into this topic!

Why is Driving With Only Water in the Radiator a Bad Idea?

Adding water to your radiator system will cause it to get contaminated. As long as you’re using the proper coolant for your car, driving with low coolant is healthier for your engine than driving with no coolant at all.


Adding water to the radiator dilutes any remaining coolant in the radiator. It makes it less effective. Protecting against corrosion, raising water’s boiling point, and decreasing its freezing point are only a few of the tasks of coolant.

It is imperative that the problem that led to a low coolant level be rectified as quickly as possible. The radiator typically loaded with an equal amount of coolant and water to prevent further damage.

Running only water in your car’s radiator will cause overheating, engine block, and cylinder head damage? Most tap water includes minerals that cause corrosion, limit radiator life, and reduce its cooling effectiveness.

Therefore, unless there is an extreme scenario or an emergency case, you shouldn’t run your radiator with simply water.

How to Use Water In The Radiator In An Emergency

Stop immediately if you discover that your engine temperature has risen. You may add water to the radiator to keep going.

In order to secure top up your radiator’s coolant with water, these are the procedures to follow:

  • Check that your car is in Park or Neutral, with the parking brake on, and the engine is off and cool.
  • Use a towel or thick cloth to loosen the radiator cap carefully. Before removing the cap entirely, take a step back and let the pressure build-up.
  • The radiator should be filled with the best water you can get your hands on. In order to get the car’s radiator cap back in place, unscrew it, replace it, then tighten it until it clicks.

Even though it’s not ideal, adding water to your vehicle’s fluids is better than leaving it completely dry.

What Kind of Fluid Works Best for The Vehicle Radiators?

If coolant isn’t readily accessible, fill your radiator with the purest water. Distilled water is ideal here. Alternatively, you can use tap water or water from a bottle.

car radiator system maintenance of opening the radiator cap

Keep in mind that mineral deposits left in your cooling system by tap or bore water can shorten the lifespan of your radiator and contribute to corrosion.

When is the Next Time I’ll be Able to Refill the Radiator with Coolant?

Find out why the coolant was so low in the first place by having a specialist inspect your radiator. Before the coolant is replaced, the technician will look for and fix any leaks, replace any damaged cooling system components, and cleanse the radiator.

Before refilling the radiator with coolant, the radiator must be flushed. An aluminum radiator’s failure can be caused, in part, by a failure to flush it on a regular basis. After the cooling system has been fixed, ask your technician to do a full radiator flush on the system.

Using a 50/50 combination of the coolant recommended by your vehicle’s manufacturer and distilled water, clean the radiator thoroughly.

In a circumstance where you must use water as the coolant, make sure you take the vehicle to a radiator mechanic to find out what the problem is and fix it.

The radiator, heater, and engine will be less likely to sustain severe damage if the radiator is repaired as soon as possible.

What Is Car’s Coolant Reservoir?

Located in the engine bay, the coolant reservoir is a plastic container holding the engine’s coolant supply. Vehicle engines release and absorb coolant while cooling down their hot bodies. It necessitates the need for an engine cooler reservoir.


A low amount of coolant pressure indicates that more coolant is needed when the engine is cold. The cooling system’s pressure rises when the engine is heated. It requires less coolant to operate.

Additionally, when the engine heats up, the coolant in the reservoir expands to accommodate this expansion. As a result, the coolant loses heat as the engine cools and flows into the radiator via the plastic reservoir tank.

Where Can I Found My Coolant Reservoir In My Car?

Coolant reservoirs are often made of rigid plastic. The engine bay on the upper right side is the most common location for its storage. Keeping the coolant reservoir in working order is essential to avoiding engine problems.


Engine damage may develop fast if your vehicle’s coolant level drops too low. It often results from a leak somewhere in the cooling system.

This might lead to hefty repair fees. A lack of boiling and freezing points in water and its inability to preserve your vehicle’s engine make it ineffective as an antifreeze substitute.

In addition, it is less efficient in absorbing heat. In the event of a vulnerable state, only clean water can be used.

But it has a certain risk. You will be responsible for your engine. Any type of occurrence with your engine may cost you a large amount of money.

Scroll to Top