The stove in the car blows cold air: reasons
Content
Car owners often encounter a situation when the stove in the car does not heat up, cold air blows, which is why the interior does not heat up and it is uncomfortable to drive in such a vehicle in winter. If you are at least a little versed in auto repair, you can restore the heating system on your own, following the recommendations that we will give in this article.
Car owners often encounter a situation when the stove in the car does not heat up, cold air blows, which is why the interior does not heat up and it is uncomfortable to drive in such a vehicle in winter. If you are at least a little versed in auto repair, you can restore the heating system on your own, following the recommendations that we will give in this article.
How driver and passenger heating works
A car stove, also known as a heater or heater, is part of a complex engine cooling system that takes away part of the thermal energy from there and gives it to the passenger compartment. The combustion of the air-fuel mixture in the cylinders leads to heating of the engine block, through the channels of which antifreeze circulates. Until the engine is warmed up to operating temperature, the antifreeze moves in a small circle, that is, it passes through the radiator (heat exchanger, heat exchange element) of the heater, after which it reaches the closed thermostat and returns to the engine water jacket.
The movement of air inside the heater occurs through two channels, that is:
- through a heat exchanger;
- past the radiator.
How car interior heating works
In the first case, the stove is switched to heating mode, in the second it works as a ventilation or in conjunction with an air conditioner. Read more about the device and the principle of operation of the cooling of the power unit and interior heating here.
Why is the oven not working?
If the heater cannot heat up normally and continues to blow cold air, then there are only 5 reasons for this:
- cold motor;
- stuck open thermostat;
- the circulation of the coolant in a small circle is disturbed;
- the heat exchange element of the stove is overgrown with dirt from the outside;
- Faulty heater damper actuator.
To determine exactly why the heating of the car cannot heat the interior properly, do a simple test:
- start the engine;
- wait until it warms up completely and the radiator fan turns on;
- feel the hoses of the large and small circles.
If the lower pipe of the engine radiator and the return hose of the small circle, suitable for the pump, are hot, but cold air continues to blow from the stove, then the first three reasons disappear, because the liquid circulates in a small circle, which means that the antifreeze through the heat exchanger cannot effectively heat the passing stream .
Next, make an audit of the interior of the heater, for which you will have to open access to its heat exchanger. Even if the defect is in the damper drive, still check the condition of the heat exchange element, because it is easier to repair everything at a time than to disassemble half of the cabin again later.
If the return pipe of the small circle is cold when the engine is fully warmed up, then somewhere in the small circle there is a blockage that prevents the circulation of the liquid, which means that a complete revision of the entire cooling / heating system must be done.
What to do
In this section, we will describe in detail how to eliminate each of the malfunctions that cause the stove in the car not to heat up, cold air blows, and also to prevent their occurrence in the future. These recommendations apply to vehicles of any make and year of manufacture equipped with an internal combustion engine and water cooling. The exceptions are electric cars and vehicles with an air-cooled motor, because the heating works on a completely different principle in them.
Cold motor
This problem is especially relevant for owners of diesel cars, because the warm-up rate of their engine is noticeably lower than that of gasoline counterparts. You can correct the situation in the following ways:
- narrow the return hose or small circle pipe;
- reduce the heat loss of the power unit by covering it with a heat-saving blanket or insulating the engine compartment;
- Install an engine preheater.
The stove does not heat up in the car - a cold engine
Narrowing the return hose / small circle pipe is effective only on obsolete cars developed before the end of the 80s of the twentieth century, in newer cars this must be done with care so as not to reduce the efficiency of the stove when the engine is fully warmed up. To achieve the effect, insert a sleeve into the hose or branch pipe, the inner diameter of which is 1,5–2,5 times smaller than the inner diameter of this element. Such a narrowing will reduce the intensity of the coolant circulation, which means that the block and the head of the power unit will quickly reach the operating temperature and will heat the coolant more efficiently.
Stuck thermostat
If the reason that the stove continues to blow cold air is a stuck thermostat, then you must understand that it is undesirable to drive such a car, because a malfunction not only reduces the level of comfort, but also dramatically increases engine wear. The slower the power unit warms up, the longer it runs on thick oil and with a rich air-fuel mixture, which increases the load on all plain bearings and the cylinder head gasket. Therefore, having discovered a problem, try to immediately replace the thermostat.
The stove in the car does not work - the thermostat is jammed
On most machines, this manipulation is easy to do, the whole process will take 15–45 minutes. Remember, if there is a suspicion that this part is jammed or does not work properly, immediately remove and check it as described here.
The circulation of the coolant in a small circle is disturbed
If the reason that the heater continues to blow cold air in heating mode is a violation of the coolant circulation, while the engine does not overheat, then disassemble the entire heating system and diagnose each part through which the antifreeze moves. Perhaps the hose is pinched or twisted somewhere, or scale has clogged the tube or heat exchanger. After finding the cause, flush or replace the part, then assemble the entire system and fill it with antifreeze. A detailed description of the process of flushing the heat exchange element can be found here.
The heat exchanger of the stove is overgrown with dirt from the outside
After making sure that this is indeed the problem, do the following:
- disconnect the battery;
- drain antifreeze;
- open access to the heater radiator;
- remove it.
The oven does not work in the car, washing the radiator
Carefully clean the dismantled heat exchanger, without crushing the fins, from foliage and other debris, then soak in any detergent and rinse it with a stream of water. High-pressure washers with adjustable water flow are well suited for this. After flushing the heat exchange element, replace the cabin filter and eliminate any defects in the heater fan housing through which road dirt got inside. Reinstall the part, fill the system with antifreeze and remove air pockets, then assemble the car and connect the battery.
Faulty damper actuator
The method of repairing this defect depends on the make and model of the car, therefore, before doing any manipulations, carefully study the operating instructions for your car, then carry out repairs in accordance with the recommendations from this document. After regaining control over the damper, the stove will heat efficiently, because the air flow will go through a hot heat exchanger.
Conclusion
The reason that the stove in the car does not heat up, cold air blows even in heating mode, is always some kind of breakdown that you can fix yourself if you have at least a little car repair experience. Now you know why such a malfunction occurs and you can repair your vehicle yourself.
