Overheating happens when heat cannot escape from the engine. The heater, on the other hand, does not operate if it does not receive enough heat. These problems might be caused by a defective radiator, coolant obstruction, low coolant level, and so on.
So what to do when the car overheats and the heater not working? To tackle these issues, you must first detect the defects and then resolve them accordingly. It’s always wise to conduct with a specialist when left unsure.
This article will go over several issues of automobile overheating and heater failures. So, if you suffer from these issues regularly and wish to find a solution, keep reading.

Signs of Car Overheating and Heater Failure
It’s necessary to figure out these problems before your car overheats to the point of failing. Signs of car overheating are:
- The engine temperature gauge of your dashboard will spike into the red or to “H’’
- Steam almost looks like smoke will come from under the car hood
- A strange and unusual smell will come from the engine area
- Car heater not blowing any hot air
Causes Of Car Overheating Along With The Heater Problem
There might be numerous reasons behind the car overheating and the heater not working. A few common reasons are:
Coolant Deficiency

When the coolant level lowers, air enters the higher pipe, causing the system to fail. Furthermore, if the level lowers, it will be unable to reach the heater core. As a result, the heater will be unable to pump hot air into the cabin.
This usually happens when the engine works too hard and overheats. Inadequate filling or coolant leakage might also be a cause.
Fault In Thermostat
The thermostat opens and shuts to regulate the temperature within an engine. But, if thermostats are faulty, they will remain closed no matter how hot the engine gets.
Thus, the cold coolant won’t be able to absorb any heat. Therefore, when you start the heater, the coolant won’t be able to provide heat to the heater.
Faulty Heater Fan

The heater fan’s job is to blow hot air into the cabin. The volume of air entering and exiting the heater core is greatly decreased when the heat fan operates slowly.
As a result, when coolant transports heat from the engine to the heaters, if the heater fan fails, the heat is not dispersed to the cabin.
Leaky Radiator
The radiator removes excess heat from the engine and cools it with fans. On the other hand, a leaking radiator will prevent the coolant from reaching the heater. As a result, there will be no heat transmission from the engine to the heater.
Clogged Heater Core

Sometimes, the coolant system can clog the car’s heating core. This might happen due to the radiator rusting from the inside or if any debris gets through the radiator.
Issues With Hoses And Belts
If coolant hoses are ruptured, leaked, or blocked and hoses are worn out, they will be unable to maintain air and coolant flow. Thus, coolant and airflow to and from the engine and heater will be disturbed.
Low Oil Level

Oil is used to lubricate engine components and prevent abrasion. This aids in the regulation of the total temperature.
As a result, a decline in oil levels may cause the vehicle to overheat. As a result, the heat is not transported to the heater, and the heater ceases to function.
Car Overheating and Heater Not Working? What To Do?
These issues are not something to linger with. It will keep damaging your car as long as you delay. So, resolve these problems by taking the following these steps:
Check The Fuses
Follow the vehicle instruction manual to understand how to check for faulty fuses. If you find any issues with fuses, replace them.
Check The Heater Fan
If there are no issues with fuses, then check if the heater fan is working properly. In case you can’t inspect this visually, turn on the engine and set the AC to its highest setting.
If you can’t hear the fan running, then you better fix or replace the heater fan.
Check Coolant Level
Check for the coolant level of your engine. If the level is low, fill it with the recommended fluid. Then, run the car engine for a while the thermostat opens and starts supplying hot coolant to the heater core.
Check For Blocked Or Damaged Coolant Hoses
Generally, It is difficult to check for damage in a heater core feeder hoses. Thus, only check damages in engine coolant hoses.
If you find any splits or holes in coolant hoses, make sure to replace them with no damaged hoses.
Call The Mechanic
If you can’t figure out the problem and how to solve it, then you better visit a garage. Mechanics will diagnose the problem and solve it properly.
Tips To Prevent Overheating And Heater Failure In A Car
You can alleviate permanent damage to your car by following these simple steps:
- Regular coolant exchanges and flushes
- Check the coolant level consistently
- Always store an extra bottle of new coolant and water in your car trunk
- Keep monitoring the thermostat while driving
- Do not overuse car AC
- Regular radiator maintenance
- Routine inspection of the car
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