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Can Low or Bad Coolant Cause No Heat? (Quick Answers)

If you’re wondering whether a low or bad coolant is too bad a situation to be in with your car, then you are thinking right.

A low or bad coolant has caused a line of problems and heating problems like no heat could be just one of them in a hundred.

Low or bad coolant cause heat

A low or bad coolant can cause no heat in a car. A low coolant problem mainly occurs due to leakages in the radiator or hose, causing the car’s cooling system to malfunction. Corrosion, rust & wear out can also cause coolant to go bad. However, if a coolant becomes dirty, the engine would overheat.

Whether it’s low coolant or bad coolant, your car’s heating system is certainly going out of the window if your car’s coolant is acting up.

Several issues may relate to a bad or low coolant. Likewise, a few reasons lead to a bad or low coolant in your car’s engine system.

Low coolant:

Low coolant is one of those problems that may not seem like the end of the world, but it can cause your car to completely put the heating system to become faulty.

Low coolant is responsible for your car to become frozen during chilly months, caused precisely by low heat. Similarly, overheating problems are also why low coolant needs to be catered immediately.

And the primary reason why there might be a low coolant is possible leaks. These leaks could mainly be in the radiator or the radiator cap.

It is possible to avoid low coolant problems that cause no heat through regular checking and maintenance, which would include replacing suspected, leaky, or worn-out hoses and caps.

Bad coolant:

Bad coolant shows the same antifreeze problems as low coolant, one of which is your car not becoming warm enough for no heat issue.

A car’s coolant can go bad, or, as they say, “sour” if it has depreciated too much and hasn’t been replaced in a while.

Due to the high acidity, the coolant becomes less resistant to any of the corrosion or rust that may eat away the radiator, pump, and sections of the coolant as well.

However, if the coolant is dirty or contaminated, it is more likely that the car would face overheating issues, as opposed to no heat issue.

Can a coolant leak cause no heat?

A coolant leak can cause several problems and no heat is one of them. Coolant leaks are easier for the eyes to detect as you would be able to spot a white element right around the valves.

Because the coolant contains both antifreeze and water, the ratio of the who has to be maintained for your car’s cooling or heating system to work properly.

One of the main reasons that a coolant leak occurs in your car’s system is to wear out the radiator. When the radiator becomes old, corrosion and rust cause the tubes to become fragile as well.

Moreover, when the gasket that closes the tank and the radiator wears away, there’s more possibility of leaks, consequently leaking to no heat issue.

Other than that, you may note that a blown head gasket could lead to a possible coolant leak.

This leak would mean that the engine oil could mix with the coolant, causing engine failure as well as no heat problem. If the coolant level is low due to the leak, the car would not be able to warm up appropriately.

Whenever there is a coolant leak, this ratio of water to antifreeze is disrupted, causing your car’s no heart problem.

Can dirty coolant cause no heat?

When you notice that the coolant has gone cloudy and starts to give off a somewhat metallic smell, it’s a sign that the coolant is contaminated.

The reason we emphasize the regular maintenance of a car’s cooling system is that dirty coolant can also cause bigger problems like engine failure.

However, a dirty coolant would not be directly responsible to cause no heat. Rather a dirty coolant can lead to the overheating of the engines.

When a coolant is dirty, sediments and dregs would accumulate in your radiator and cause a blockage. This would mean, that the coolant would not be able to cool the engine, causing overheating.

Overheating can cause an engine to become damaged to the point that you would need to replace more than one part to get your car started again.

Can a bad coolant temp sensor cause no heat?

One of the major reasons why your car is exhibiting some no heat issues and hence not blowing war air has to do with the thermostat.

Now it is simple to guess that once the thermostat in a car starts to become out of order, the temperature sensor would in turn start to malfunction.

If the temperature sensor in a car is unable to detect whether the car needs heating or cooling, you can expect that a bad coolant and hence a faulty temperature sensor would cause no heat.

As the coolant flows from the radiator to the engine, what controls the speed and quantity of the flow is the thermostat. If the thermostat is not working properly, it could get stuck in the open position.

If the valve is stuck in the open position, this would mean that there is an increased flow of coolant. This would cause the car to drop in temperature, even though it needs to heat up to reach the optimum driving temperature.

Unable to detect what is going on, the temperature sensor would not be able to turn on the heating system.

3 reasons why low or bad coolant cause no heat

Now that it has been established that a low or bad coolant can cause no heat, you would need to know why this happens.

Here are a few possibilities:

Problem with heater core:

The primary reason that makes low or bad coolant cause no heat is the problem with the heater core. With the help of a blower fan, heat is dissipated to the back of the car from this heater core.

Because the heater core is made up like a maze, with tubes and tunnels of wires, it may clog up quite easily.

When it gets clogged up, the coolant flow is constrained and becomes low. Vise versa, when the coolant is bad, the heater core passage may get clogged up.

One way or the other, it can be seen that the bad or low coolant causes the heat from the heater core to become disrupted.

Leaky radiator:

When there is a leaky radiator, different parts of your car’s system including the engine and the cooling system will start to malfunction.

When there is a radiator problem, the first sign of a possible car issue is how your vehicle heats up.

Although in most cases, there would be overheating of the engine, the coolant being low can consequently cause the system to stop the blowing of hot air.

Similarly, the coolant can go bad or low when the radiator cap or hose is worn out.

Bad coolant:

When we say bad coolant, what we mean by that is the quality of coolant is compromised, or more precisely, contaminated.

A bad coolant will have similar effects on the radiator, only in the long run. When the coolant is bad, the mixture of the antifreeze and water in the coolant is not optimum.

The ratio of these two elements must be kept optimal so that the car’s system can heat up during colder days.

However, if the coolant is bad, the car’s heater is unable to blow this hot air, again causing no heat problem.

Quick fix for no heat in car for low or bad coolant:

Here is a quick fix for no heat problem in the car for low or bad coolant:

  • At first, you may want to burp the air out of the coolant system. Next, you may want to wait till the car cools down to a workable temperature.
  • Turn off the engine and remove the radiator cap and the valve.
  • Using a funnel, add the coolant to the reservoir. You would want to add the coolant until there is no air bubbling in the passage.
  • With the blower motor fan set to low, you would now want to start the engine. Control the heater as you let the engine run for a good 20 minutes.

Final Thoughts

Low or bad coolant can cause a string of problems, which can lead to a car having no heat issues. This means that the car would not heat up at all during winter days due to a faulty heater core. Low or bad coolant is caused when there are radiator leaks, old tubes, or water evaporation issues.