Cooling is a solution necessary for the stable operation of the car (the task is to cool the engine and heat the interior).

Below we will explain the questions regarding what will happen if the coolant is low and everything you should know about it

What happens if the coolant is low?

The coolant level in the expansion tank must be between the two drawn lines indicating the minimum and maximum value.

Lack of coolant in the expansion tank can cause serious engine overheating. Firstly, it is quite easy to “fill” the entire coolant “circuit” with air.

This will immediately cause overheating of the powertrain and it is likely that the coolant will also boil, but that’s the best outcome.

Most often, the complete absence of coolant leads to serious problems:

  • The engine can easily jam due to severe overheating 
  • The piston pins will stick to the piston
  • Piston rings, as well as oil scraper rings, will simply stop springing and lie down in the piston.
  • The metal will oxidize (thermostat, pump impeller, radiator, etc.)

Secondly, the cylinder head gasket will receive a portion of damage, after which the sealing element will have to be replaced, and the cylinder head will need to be given for milling.

In the case of engines with an aluminum block, the damage will be much more serious.

Reasons Why The Coolant Is Low

Unfortunately, this problem is widespread today, and among the factors affecting the level of coolant, the following can be distinguished:

1. At minus temperatures, the coolant loses some of its volume. That is why it is recommended to constantly monitor the coolant level in winter and to refill it if necessary.

2. There may be cracks in the expansion tank through which the coolant is leaking. By the way, it is very hard to detect such damages, as their appearance is more like ordinary scratches. But still, a small crack is enough for the coolant to leak.

3. The presence of leaks, as a result of which it lost its tightness. Often the reason lies in damage to the pipes and connecting hoses, so it’s important to do a complete revision of the pipelines if you suspect leakage. It may be that the thermostat gasket is damaged, or a leak has formed in the radiator.

4. Since the main component of the coolant is water, which has properties to evaporate, the volume of coolant in the system decreases accordingly. It is necessary to add that loss of coolant within the low and high marks.

As can be seen, it’s not always leaking that causes a drop in the coolant level. A small volume of coolant can simply evaporate from the system, even if it is completely sealed.

How To Check The Coolant Level

Checking the presence of coolant in the expansion tank is quite simple, all you need to do is open the hood on a cold engine and look at the coolant expansion tank itself.

It should show the marks that determine the minimum and maximum allowable amount of coolant. If the coolant does not go beyond these limits, then everything is fine.

In modern cars, sensors are being installed that indicate the amount of coolant you have. This system will alert you if the coolant level is too low or too high.

Engine Cooling System Failure

Why does the engine cooling system not work properly? In most cases, it is caused by low coolant levels. This can be determined by the following indicators:

  • The exhaust fumes are white
  • The engine starts to smoke
  • The heater does not work or does not work well
  • A signal is lit on the dashboard to indicate that the powertrain is overheating
  • Increased oil temperature and pressure.

It is worth noting that often all the signs described above appear simultaneously, so do not operate the engine too much, but rather immediately turn it off and take diagnostic measures with subsequent repair of the engine cooling system.

How Often Should I Put Coolant In My Car?

Coolants lose their effectiveness over time. The acidity increases and the corrosion protection reduces.

The average operating life of coolant is three years or 60,000 km of mileage (with a density of more than 1.075 kg/cm³).

There are carboxylate compositions on the market, which can work up to five years (and sometimes even 10).

It is always recommended to follow recommendations from the car manufacture when choosing a coolant/antifreeze

If The Engine Is Overheating

The times given above are irrelevant when there are signs of engine overheating. There are situations where an urgent replacement is needed.

First of all, it is necessary to check the coolant level before proceeding.

Methods below will describe how to check the condition of the coolant:

1. Coolant Test Strip (apply a little of coolant with the reagent, the marks on the package determine the condition of the coolant)

2. Visual Inspection (foam or discoloration of the coolant are a signal for an urgent replacement of the coolant)

3. Testing By Boiling (bring a tablespoon of coolant to a boil over the gas, if there is an ammonia smell or granules, you should not use this coolant).

How Long Can You Run An Engine Without Coolant?

If the coolant level drops to a critical level, there is a risk of overheating the engine and having a costly repair. But if you have not damaged the radiator and the coolant has not leaked out, it means that some coolant is still present in the system, so you can go to the nearest store and buy it, then fill the coolant to the desired level (the average mark).

Coolant volume in high/low temperatures

The amount of coolant in the “circuit” directly depends on its temperature and weather conditions. In the hot season, the coolant in the expansion tank will always be close to the max mark, while in winter it can be seen at the min mark. This is due to thermal expansion. The colder it is, the less volume it has.