The stove does not heat up at idle: reasons and solution

If the stove works, but does not heat (cold air blows)

First of all, it is important to understand the basic operation of most car heaters. There are exceptions, but heaters that use water-cooled engines use very hot coolant to warm the interior of the car.

This is achieved by running antifreeze through a special component called a heater rod, which is similar in design and functionality to a small radiator. When the fan motor draws air through this heat exchanger, this air enters and heats the interior of the car.

If cold air blows from the heater deflectors, even when the car is warm enough, there may be several reasons:

• low coolant level;
• blockage in the heater line;
• the heater dampers do not work;
• heater valve stuck;
• Electronic problem: bad switch or broken wires.

After the car has been turned off, some time has passed and the pressure in the cooling system has dropped, you can start by checking the coolant level. If the antifreeze level is low, then this may be the cause of the furnace stopping working - the hot antifreeze simply does not circulate sufficiently through the heat exchanger to receive heat from the furnace, and therefore cold air is blowing from the latter.

Filling the coolant may solve the problem, however, a low coolant level itself often indicates another problem - leaking through a gasket or hose, or in the worst case, even burning coolant in the combustion chambers of the engine.

If the check shows that the antifreeze level is normal, then you can start the engine again and let it warm up, and then check the temperature along the coolant flow line where the main heater hoses enter the main heater housing. The safest way to do this is to use a non-contact infrared thermometer called a pyrometer. If all the main hoses are within the same temperature as the vast majority of the coolant line, but one of the hoses is cold, then there is likely a blockage in the heater coil

If the vehicle uses a valve in one of its heater hoses, it is also important to check the operation of that valve. If the valve is jammed, then the reason for the non-working stove most likely lies in it

Internal damage to the heater radiator

In addition to a clogged radiator, some VAZ car owners have discovered another factor why the heater blows cold air at idle. In the heater radiator there is a partition between the coolant supply and outlet pipes. It may crack or crumble, preventing proper fluid circulation inside the radiator.

We recommend: Replacing the Lada Granta alternator belt with air conditioning and its tensioner

The problem can only be detected after disassembling the radiator, so it is better to have a working part on hand to check. If installing a working radiator solved the problem, you can simply throw away the old one. It is unlikely to be repaired.

Finally, I would like to advise you to monitor the correct operation of the engine cooling system of your car, use only high-quality coolant (read our article about whether it is possible to mix antifreezes of different colors - https://avtopub.com/antifrizyi-raznyih-tsvetov/) and adhere to the recommendations manufacturer!

Why doesn't the stove heat well?

There are several known reasons indicating that the stove heats well only at high speeds:

• There is air in the heating system. The stove does not function normally when air gets in when replacing antifreeze. It can also get into the heating system if the integrity of the cylinder head is damaged.
• The heater radiator is clogged. There are several reasons why the heater radiator is clogged inside and outside. From the outside, it gets clogged through the protective casing, as a result of which dust, leaves, insects, etc. get into the stove radiator. The inside of the radiator becomes clogged exclusively during operation with various dirt and deposits that are present in the engine cooling system, as well as due to the use of low-quality antifreeze.
• Thermostat is faulty. The thermostat in your car may become stuck open and closed. Moreover, if the stove heats well only at high speeds, but poorly at low speeds, most likely the reason is that it is jammed in the open position.
• Fan failure. The function of a fan in a car is to pump air into the cabin; if it works poorly due to failure of the bearings or graphite brushes, unstable operation of the heating in the cabin and the entire ventilation system will occur. Also, the cause of fan failure may be a problem in the electrical power circuit.
• Heater valve malfunctions. As a rule, such malfunctions occur only in car heaters of domestic brands: the rubber bands may dry out, the valve lever may wear out during operation or become sour.
• The cabin filter is clogged. Severe contamination of the filter is the reason why the car only heats up while driving. It should be replaced once a year.
• Damage to the stove control unit. This malfunction also causes trouble for owners of domestically produced cars. Malfunctions in the operation of the control unit can be caused by a breakdown of the air temperature sensor.

These are not all the reasons that affect the operation of the car’s heating system, but these are the ones that most often arise among motorists.

Low coolant temperature

Sometimes the heater doesn't work because the antifreeze is too cold. In this case, the radiator simply does not warm up to operating temperature. There may be several reasons for this phenomenon:

• Low air temperature
  . During short trips in winter, the engine does not have time to warm up. To avoid this, it is recommended to insulate the engine compartment. In this case, warming up will be accelerated;
• Thermostat malfunction
  . In some cases it gets stuck in the open position. At the same time, the antifreeze circulates in a large circle, and it does not have time to warm up properly. When supplying cold air into the cabin, be sure to check the thermostat.

It is also recommended to warm up the engine to operating temperature before leaving, and only then start driving.
Conclusion

. Probably all car enthusiasts know that problems with interior heating usually arise in winter. The reason for this is the intensive use of the stove. Therefore, it is in winter that people most often ask why the stove blows cold air at idle. In fact, this question is quite complex. To identify the source of the problem, you will need to go through almost the entire cooling system of your car.

Damper repair or replacement

It happens that the damper is “stuck” - that is, it stops turning due to the fact that the fastenings have oxidized and have not been looked at for a long time.

In the VAZ 2110, you can only “get close” to the damper from under the hood. First you need to remove the deflectors, then bend the antennae. Now try to move the flap by hand.

If it works and “walks” easily, then the reason is something else. But in any case, knowledgeable car enthusiasts recommend replacing the plastic damper with an aluminum one.

This small modification allows for better heat retention, the stove will work better, since, plus, there will be no deformation, which plastic dampers are prone to.

Preventing the operation of the stove in the car

In order for the stove in your car to heat well and not let you down at the most inopportune moment, you need to follow a few simple tips.

1. Keep the radiator clean. Light contamination from the outside of the radiator can be removed with a vacuum cleaner. Flushing the engine cooling system, with which the heater radiator is inextricably linked, will help get rid of internal deposits and blockages in the channels.
2. Use good antifreeze. High-quality antifreeze is the key to long-term operation of not only the stove in the car, but also the engine. Remember this and do not forget to replace it in a timely manner.
3. Change the cabin filter more often. A clogged cabin filter will certainly create problems not only for the operation of the stove, but also for the air conditioning and cabin ventilation system as a whole. In addition, dust and pollen deposited in the filter can pose a serious health hazard (especially for allergy sufferers).

If, at an outside temperature of minus 25 °C, your car’s heater heats the interior to +16 °C from below and up to +10 °C from above, then it can be considered quite serviceable. To avoid problems, it is recommended to carry out preventive measures in a timely and responsible manner that will allow you to enjoy a comfortable ride in a well-warmed-up car.

And remember, the longer the service life of the machine, the more attention its heating system requires. This applies to all cars, regardless of country and manufacturer

The principle of operation of the stove in a car

To clearly understand all the processes, it is important to understand how a car heater works. Simply put, the liquid circulating in the cooling system also passes through the additional heater radiator (heater radiator). The heat from the radiator is blown into the cabin by the fan through the deflectors.

Taking into account the fact that the heater system consists of several elements and interacts with the engine cooling system, it is necessary to understand which “link” is the cause of malfunctions and malfunctions in the heater.

Sensor that measures the temperature in the cabin

It is located in the ceiling of the Lada Kalina, close to the lighting lamp and perceives the temperature regime of the atmosphere inside the cabin. The element can also affect the operating mode of the stove. This occurs by comparing the actual temperature with the parameters set by the driver on the dashboard. Thus, the electronics adjusts the position of the dampers based on the “scanned” situation, and it seems to the driver that the stove has stopped responding to his “requests”. The reason for the disagreement is usually the banal oxidation of the contact group of the sensor, due to which it ceases to function correctly. The solution to the problem is to clean the contacts or replace the component.

Clogged radiator

Over time, scale forms in the radiator, which creates plugs. The obstruction of the lines leads to a decrease in the pressure that supplies warm air. At high speeds there may be an increase, but at idle you won’t get any warmth. What to do? Theoretically, you can try flushing the radiator yourself. Many auto stores offer special mixtures that destroy salt compounds. But purging and flushing will only work if the lines are not completely clogged. If there is no circulation in one of the pipes, then it will not be possible to flush it. Replacement only. Advice may also include checking the thermostat, replacing the filter (if available), and the gasket. But in practice, the stove does not heat up at idle in 90% of cases precisely because of the high wear of the radiator. To avoid such problems, it is recommended to take preventive measures in time. Use a high-quality cooling mixture, change it regularly, monitor the quality (after draining, for any impurities), do not mix several models of antifreeze. Operate your car competently and enjoy a warm car in winter.

Why does the heater blow cold at idle?

The essence of the reason why a cold heater at idle in most cases comes down to problems with the engine cooling system. So, there are FIVE main reasons for this situation and several less common ones:

Insufficient coolant level in the system. This is the most common and easiest option to fix. In such a situation, even significantly heated coolant is not able to sufficiently warm up the interior heater

Please note that a low level of antifreeze in the engine cooling system not only causes the heater to blow cold air at idle, but also harms the engine itself, as overheating occurs, which leads to a decrease in its overall life. This problem is an indicator of the failure of its individual parts, or a change in their geometry.

Formation of air jams

Air in the cooling system may appear due to depressurization of individual pipes or their connection points, improper replacement of coolant, malfunction of the air valve, problems with the pump, or a breakdown of the cylinder head gasket. Air locks impede the circulation of antifreeze in the system; as a result, the stove heats only when moving, and at idle cold air blows from the deflectors.

Faulty water pump. This unit is responsible for circulating fluid through the system and when the impeller is not able to create sufficient flow, the heater blows cold air at idle, and when the car is moving it can be a little warmer.

Dirty heater radiator. The heater radiator tends to become clogged over time. As a result, heated liquid begins to pass through its honeycomb poorly. And this, in turn, will lead to the fact that the stove fan drives barely warm, or even completely cold, air.

The coolant supply is cut off. If the stove has a valve for supplying fluid to the heater radiator, then it may be that the car owner simply forgot to open it, having closed it in the summer, or it is jammed in a half-open or completely closed state. This is especially true for domestic cars, especially quite old ones (for example, VAZ “classic”, Moskvich and other cars of Soviet design). Typically, taps simply rust, especially when, instead of factory-made antifreeze, the car owner uses ordinary water as a coolant, especially “hard” water, that is, which contains a significant amount of salts of various metals.

Thermostat failure. When the thermostat rod sticks in the open state, this will be the reason why the heater blows cold at idle. If in a cold engine the coolant initially circulates in a large circle, it will only be able to warm up after the car has been driving for a long time, or it will take a lot of time to warm up when the engine is idling.

Problems with the operation of the climate control system. Modern cars equipped with this system sometimes experience software malfunctions, which leads to a situation where the heater does not heat up at idle. Problems may be associated with either incorrect configuration of a particular system, or a software or hardware failure of the climate control.

Main reasons

Why does the heater blow cold air at idle? This is usually due to poor supply of coolant to the heating radiator. Therefore, all breakdowns here are closely related to the cooling system. Most often, the reasons are as follows:

• There is not enough coolant (for example, if antifreeze leaves the expansion tank);
• The damper is closed;
• The coolant is not supplied to the radiator. Blockage in pipes:
• The antifreeze supply is blocked;
• The pump is faulty;
• Air locks in the system.

All this needs to be checked; one of the problems will definitely be found.

Liquid level

. This reason usually occurs in young drivers and girls. These two groups of car enthusiasts often forget to control the level of antifreeze. But sometimes more experienced people also encounter this. When supplying cold air from the stove, you must first check the antifreeze in the expansion tank. If it is not enough, then you need to add it to the minimum level. Usually, this helps to cope with the problem.

Damper closed

. On many cars, air flow is regulated using a complex system of deflectors and dampers. Perhaps you have them in the position of supplying outside air directly into the cabin. Check this moment. Often this is where the repair work ends.

The design of the heating system of the VAZ-2110

The concept of interior heating on the VAZ-2110 remains the same - the air supplied to the cabin is heated by the cooling system. To do this, a radiator is installed in the cabin, under the front panel, which is included in the cooling system; heated antifreeze moves through it. The air passing through the radiator is supplied through the air intake. After heating, the air flow through the air ducts is supplied to the necessary areas - the windshield, legs, torso.

Forced air circulation is provided, which increases the efficiency of the distribution of warm flow throughout the cabin. For this purpose, the stove is equipped with a fan driven by an electric motor.

The air heating temperature is regulated by dampers. One of them allows the flow either through the radiator (for heating) or bypassing it. The damper divides the flow to obtain the desired temperature - one part of it goes through the radiator, and the second bypasses it, after which it is mixed, the degree of heating is regulated and supplied to the air ducts.

The second damper is designed to shut off the air supply to the cabin from the outside. Thanks to it, a closed air circulation mode is established.

Advice from auto mechanics

To tune the VAZ heating system, its circuit diagram is studied. The system can be modified to block the air flow to the rear of the car using foam. The factory thermostat is also being replaced with an analogue one with 6 holes. In this case, the temperature in the cabin will remain longer, and the stove will heat better. Another way to modify the standard 2110 heating system is to install a plug for the deflector.

If your car has air conditioning, it should only be turned on in wet weather. In winter, the stove turns on and directs the air onto your feet or onto the glass.

To ensure good operation of the heater, the nozzle is raised above the lining. Before starting the stove in winter, it is recommended to clean the glass from moisture.

Problems with the cooling system

When the heater on a VAZ-2114 does not work, reasons other than electrical may lie in the coolant circulation system:

1. Airlock. As the coolant cools, air accumulates in the upper part of the radiator. Subsequently, air enters the thermostat and a large circle of coolant movement is blocked. The heater core remains cold. There are many ways to fix the problem. But the easiest thing is to squeeze out excess air from the system. To do this, unscrew the cap from the tank. With the engine running, the cold hose is intensely compressed, causing air to escape into the reservoir. If this method does not work, you will have to disconnect the hose to remove the air lock.
2. Radiator. Few people devote time to maintaining their car, and especially the heating system. The internal space becomes clogged with dirt, which impedes the flow of coolant. The outer multi-cellular surface becomes clogged with dust and foreign objects, which interferes with heat transfer. In this case, only cleaning the radiator and replacing the cabin filter will help.
3. Water pump. Wear of intake blades leads to a decrease in productivity and, consequently, a drop in pressure. Reduced idle pressure is unable to supply heated coolant to the radiator. Only high engine speeds allow you to create the necessary pressure.
4. Low coolant level. An antifreeze level below the minimum provokes airing of pipelines. You just need to add antifreeze to the maximum level.
5. Cylinder head gasket. A gradual decrease in coolant level, intense white smoke from the exhaust system and the smell of gasoline (oil) in the tank indicate a burnt-out gasket. Through the gap that appears, antifreeze enters the cylinders and into the crankcase with oil. Replacing the gasket requires removing a large number of parts.
6. Thermostat. The operating principle of the thermostat is based on the property of a certain metal to change its original shape when the temperature rises. If the element fails, the coolant moves in a small circle without entering the heater radiator. In this case, only replacing the thermostat will help.
7. Faucet. It regulates the flow of coolant, that is, the temperature inside the car. If it breaks, the fluid flow stops. Although it is held on by two screws, it is installed in a hard-to-reach place, under the dashboard, which is associated with certain difficulties.
8. Hoses. Connecting rubber hoses become unusable after prolonged use. They crack and break. Through the formed cracks, the system depressurizes, and consequently, antifreeze leaks, air gets inside, etc.

The stove blows cold at low speeds: causes and solutions.

We always say that everything in a car is interconnected, therefore, if one of its elements breaks down, the source of the problem must be looked for in everything that is directly or indirectly connected with this element. The cooling system is no exception. It can produce cold air at idle under the following circumstances:

• there is too little coolant in the expansion tank;

This is perhaps the most common option. Agree, even though we know that the amount of antifreeze in the system needs to be checked before each trip, we don’t always do this. As a result, the coolant level may become critically low, that is, insufficient to cope with its functions at low speeds.

What to do: check the coolant level in the expansion tank and, if necessary, top up to the required level.

• air pockets have formed somewhere;

In cases where work has recently taken place that requires replacing or partially draining the antifreeze, the reason that the heater is blowing cool may be air pockets formed inside the tubes, which simply do not allow the coolant to circulate normally.

What to do: put the front of the car on a hill, unscrew the cap from the expansion tank, start the car and wait until it warms up - you will notice bubbles appearing as soon as they pass - turn off the car, wait until it cools down a little (so as not to get burned) and return the cap to place.

• pump is faulty;

Another problem that may cause warm antifreeze to not reach the heater is a faulty water pump.

What to do: detecting this problem is often quite simple by the characteristic knocking and rumble. If you haven’t noticed one, watch your vehicle; if it gets very hot, even to the point of boiling, remove the pump and disassemble it. If the impeller lives its own life or does not spin at all, replace it or the entire water pump.

• radiator tubes are clogged

A very common option, along with an insufficient level of coolant: salts and dirt gradually accumulate on the walls of the tubes supplying coolant to the radiator during operation, and over time there are so many of them that hot liquid cannot even pass through them. As a result, the radiator remains cold, as does the air passing through it.

What to do:

Option 1: Flush the system. To do this, drain the coolant present in it, and in its place, fill in a special cleaning composition or a concentrated solution of citric acid. Start the engine and let it warm up to operating temperature. Drain the cleaning solution and add fresh coolant.

Option 2 (usually used only if the previous method was ineffective). Replace the tubes and radiator.

• coolant supply is cut off;

Almost every modern car is equipped with a tap that allows you to shut off the supply of antifreeze to the heater. It allows you to avoid the risk of overheating the interior in the warm season, but at the same time, being a weak point of the heating system, it can create additional troubles.

What to do: check the position of the tap and open it if necessary. If the faucet is jammed, it must be replaced.

A little advice: if you own a VAZ , we advise you to overpay a little and purchase a faucet not of domestic production, but of the Audi brand - with it you will not have to replace it every six months.

• low coolant temperature;

The last situation in which the heater can give off cold is cold antifreeze. And it can be like this in two cases:

1. it's too cold outside, so on short trips the engine simply doesn't have time to warm up

What to do: insulate the engine compartment.

1. The thermostat has broken down - it is stuck in the open position, as a result of which the coolant “drives” in a large circle, not allowing it to warm up properly.

What to do: check and, if necessary, replace the failed part.

Heating system design

The VAZ 2110's interior heating system has its own differences. First of all, it should be noted that the system works separately.

It is represented directly by the heater - a stove that prepares warm air entering the cabin through pipes - heat distributors. Air ducts lead into the cabin, where hot air flows directly from the control panel, and also blows on the windows or is directed to the driver and passenger's feet.

Control parts and air ducts of the VAZ 2110 stove

All this is controlled by a unit for regulating the air flow and its temperature (heating), that is, an air distributor. The VAZ 2110 stove has one more difference from others - it has an evaporator.

Advice from experienced car owners

Eugene:

“I never thought I would encounter such a problem, but it happened. After repairing the cylinder head, it became very difficult to warm up the interior. I spent a long time searching for why, and it turned out that the engine was throttling. I did everything as advised, the coolant stopped bubbling only after 4 hours, but now it’s always warm in the cabin.”

Sanya:

“I have a VAZ 2109i, it blew cold at idle. I added coolant to the expansion tank, everything was ok.”

Rustam:

“I drive a 6th Mazda. Last winter, the heater began to act like a fool: over 2 tons of revolutions, hot air came out of it, over 3 tons, despite how much the temperature was set, the heater practically boiled with boiling water, but as soon as you stopped, the air became cool. I went through all the possible options described in the article, the problem did not go away, after a long search, the service station technicians found the reason - the climate control system had failed.”

We recommend: Do-it-yourself valve grinding when repairing the engine head

Ruslan:

“On my Priora, the stove also blew cold at idle, so to fix this I had to constantly add antifreeze. Got tired of it, sealed the lower pipe, now everything works properly.”

Oleg:

“As a service station worker, I can say that the warmest stove among all domestic cars is in Kalina, but sometimes it also malfunctions. As a rule, the whole problem lies either in the gasket of the pump, or in the pump itself, so if you are the owner of the named car, in which case the first thing you should pay attention to is the pump and its components.”

Causes of poor-quality stove operation

Based on the complex structure of the stove, it becomes clear that it may not work correctly for many reasons. A malfunction of at least one of the components and components of the heating system can lead to a malfunction of the stove. In this case, a malfunction may occur due to the driver’s fault, or it may be a consequence of aging or incorrect operation of other vehicle systems.

Problems with the stove can manifest themselves in the following ways:

1. Poor interior heating.
2. Cold air from the stove.
3. Variable temperature of air supplied from the stove.
4. Weak flow of hot air from the stove.
5. The heater in the car does not turn on.

Knowledge of the structure of the stove itself and possible breakdowns will make it possible to avoid large expenses when repairing a car. Let's look at the most common causes of poor-quality stove operation below.

Fan doesn't work

A fan malfunction can often be one of the problems with heating the interior. The cause of this failure is usually damage to the bearings or graphite brushes, which may require complete fan replacement. Also, the fan may be faulty due to the blown fuse or relay in the electrical power circuit, which is also a reason to contact a car service center.

If the fan makes a whistle during operation, and its rotation speed changes from minimum to maximum and vice versa, then the cause of the problem may be a failure of the fan motor. In such conditions, the radiator may remain hot, but it will not be possible to warm the interior to the desired degree.

Insufficient coolant level

A malfunction of the stove can be caused by a coolant leak, as a result of which heat stops flowing into the cabin radiator in the required volume. This in turn leads to a decrease in the volume of antifreeze in the expansion tank. To fix the problem, you need to find the location of the leak, add antifreeze to the expansion tank, and sometimes it may be necessary to replace the coolant supply valve.

Engine pump faulty

The pump is used to circulate antifreeze and to ensure proper functioning of the stove. If such a pump breaks down, a malfunction may occur in many engine components, including the vehicle interior heating device.

A malfunction of this part can be caused by wear on the inside of the impeller, a broken crankshaft belt, or even jamming of the pump itself. It is better to eliminate this kind of problem by completely replacing the pump, and to avoid such breakdowns, it is recommended to regularly check the hose leading to the pump, and also listen to sounds under the hood.

Blown engine head gasket

The head gasket is designed to connect the block and the car engine head itself, ensuring tightness and preventing coolant and fuel from mixing with each other. Burnout of the gasket in the engine cooling jacket leads to the generation of exhaust gases, which can enter the cooling system through the pipes. In this case, the heat exchanger becomes airy and the efficiency of its operation decreases, the coolant can heat up, and malfunctions are observed in the operation of the stove.

Thermostat malfunction

The thermostat is a device directly involved in the circulation of coolant, so its malfunction will affect the air temperature in the cabin. Since the thermostat can be in an open or closed position, its failure is characterized by jamming in one of these positions.

If the thermostat is stuck in the closed position while driving in city traffic, the temperature of the antifreeze may increase, and subsequently the engine may overheat. When stuck open, the interior temperature will be low when driving in high gears, while the temperature will remain normal at low speeds.

Heater core blockage

The heater radiator can become clogged for various reasons, and this can happen both from the outside and from the inside. For example, the outside of the radiator may become clogged due to dust, leaves, and insects entering through the protective casing. On the inside, clogging occurs due to dirt and deposits that can form in the engine cooling system.

Cabin filter clogged

A heavily contaminated cabin filter is one of the common causes of stove malfunctions. Many drivers treat it quite dismissively and do not replace or throw away the old one for a long time.

It should be remembered that a clogged filter is an obstacle to the flow of heated air into the cabin. In addition, when the filter is clogged, dust and mold spores can enter the cabin and accumulate in the filter itself.

Why is cold air blowing from the stove?

If the stove blows cold air, problems can be divided into the following groups:

• elements of the engine cooling system are faulty;
• the problems are related to the heater system itself;

You need to start by checking the engine cooling system. In this case, it is important to accurately identify the problem, since system malfunctions can lead not only to heater failure, but also to serious problems with the engine itself, automatic transmission, etc.

Engine cooling system malfunctions

The check should begin by assessing the level and quality of antifreeze in the expansion tank. If the coolant level is normal, but has changed its properties, is heavily contaminated, flakes, clots or a large amount of rust are visible in the liquid, such antifreeze must be changed urgently.

You also need to inspect the radiators, all pipes and connections, as well as the area where the pump is installed (leaks are not allowed). Regardless of whether coolant leaks are visible or not, you need to check the fluid level in the cooling system reservoir. Normally, the level should be between o and “max” (middle of the tank).

• The first element that can fail is the cooling system thermostat. For example, if the thermostat does not close and fluid circulates in a large circle, the motor will not be able to reach operating temperature. As a result, the antifreeze will be cold and the temperature of the liquid will not be enough to heat the air from the heater radiator.

To check, you can follow the coolant temperature gauge. If the engine does not warm up for a long time, the indicator needle will not rise either. You can also manually probe the pipe from the main radiator. If the hose does not heat up and the heater blows cold air, there is a high probability of problems with the thermostat.

• The water pump (cooling system pump) may also be faulty. If the pump does not work normally, the process of pumping antifreeze through the system is disrupted. In this case, the problem may be related both to the pump itself (for example, the impeller is destroyed or the pump is jammed) and to the pump drive. In this case, the engine can quickly overheat, while at the same time the heater, open to the maximum, blows warm or even cold air.

You may notice that when the engine speed increases, the heater blows hot air, but at idle and low/medium speed the air becomes cold again. This also indicates that there is not enough coolant flowing through the heater (the pump is not pumping).

• Another malfunction is a breakdown or burnout of the cylinder head gasket, damage to the cylinder block, etc. Typically, if the cylinder head gasket is damaged, it will allow gases from the cylinders to enter the coolant. If the block is damaged, oil may get into the antifreeze.

If the engine smokes white, the antifreeze level is increased, gurgling sounds appear in the expansion tank, foaming of the antifreeze is visible, traces of oil are visible in the coolant, then the problem is serious and requires immediate repair of the power unit.

• Air in the cooling system is also a common cause of cold air blowing from the stove. If the coolant level is normal, the heater works at high engine speeds, and when the speed drops the air is cold, the problem is air pockets.

In this case, air often accumulates in the area of ​​the heater radiator, as a result of which the heater works worst at low speeds. By the way, after increasing the speed, you can hear a gurgling sound in the area of ​​the stove. When diagnosing a malfunction, it is important to determine the reason why the seal of the cooling system is broken.

As for removing the air lock in the heater radiator, you will need to disconnect the hoses from the radiator, then pour coolant through the upper pipe until the liquid begins to pour out through the lower hose. You need to pour until air bubbles stop coming out of the hose.

You can also leave the car with its nose up, open the expansion tank cap, start the engine and rev it hard. This also allows air to be removed from the system.

Heater problems

Often, stove malfunctions are not directly related to the cooling system. In this case, it is necessary to determine why cold air is blowing from the stove and what malfunctions of the heater itself may occur.

If hot air does not blow, the following may fail:

1. damper control system;
2. heater radiator;
3. heater tap (on old cars);
4. heater fan.

It is not difficult to check the operation of dampers and fans on many cars. If the machine has a mechanical adjustment unit, then just turn on the fan and then move the regulator to the cold and hot air positions. If the fan blows air into the cabin, this indicates its functionality.

The dampers are a little more complicated. It happens that only certain positions work (blowing on the glass, on the legs, etc.). At the same time, it is not possible to blow warm air directly onto the driver or into the passenger compartment even after moving the regulator to the desired position. In this case, the stove itself works, but there is a problem with the dampers.

We also recommend reading the article on how to replace the heater radiator and heater tap on a VAZ 2114. From this article you will learn about the features of replacing the heater radiator and heater tap, as well as what you need to pay attention to when replacing these elements.

The situation is even more complicated on cars with climate control. In this case, the active functions are performed by electronic-mechanical devices. It often happens that malfunctions in the electronics lead to system errors and the stove blows cold air instead of hot air in different modes.

As for the radiator and heater tap, in this case the following breakdowns can be identified:

• the faucet does not open;
• The heater radiator is clogged.

Let's start with the heater tap, which is found on older cars (modern ones use dampers). If the faucet does not open, both the faucet itself and its drive may fail. The drive is often cable driven, the cable falls off and the faucet cannot be opened. In any case, the drive needs to be repaired or the stove valve replaced if it malfunctions.

Now let's move on to the stove radiator. In this case, it is quite simple to understand why the stove is not blowing. The thin channels of the heater core gradually become clogged with dirt, rust and deposits. As a result, the coolant cannot circulate normally through the radiator.

By the way, if sealant was poured into the cooling system, antifreeze was not changed for a long time, or ordinary water was poured instead of coolant, and the radiator itself is old, it becomes clogged. The problem is solved by flushing or replacing the heater radiator.

The stove doesn't blow at all, what's the problem?

If the heater fails, you can do the initial fault diagnosis yourself.

Unfortunately, the complex heater control system has not proven itself as a device that allows you to take the hassle off the driver and automatically maintain the set temperature. Instead, we got a lot of trouble and cold interiors in the frost. Let's go from simple to complex and first let's look at the problems with the electric heater motor. Everything is more or less simple here:

1. Fuse. We turn on the stove, it doesn’t work. If we were lucky, the fuse had blown. Finding it is as easy as shelling pears, it is more difficult to find out the reason for its burnout. The 25-amp fuse F18 is located in the main mounting block; it also protects the circuit for the glove compartment lighting, heated rear window and is partially related to the cigarette lighter, so it is easy to diagnose its failure. And in order to find the short circuit that caused it to burn out, you will have to call all these circuits - the glove compartment light, the rear window heating, the headlight washer and the cigarette lighter.

   Heater fuse location.

2. Contacts. A very common occurrence on the VAZ 2110 is the lack of contact on the heater control unit or on the electric motor itself, there is no contact on the power wire on the automatic control system. You will have to go through and clean all these contacts.

   We check the contacts on the heater control unit and the electric motor.

3. Stove blower. The electric motor of the stove also does not last forever and can either simply burn out or fail for another reason. To check its operation, we get to its power supply contacts and measure the voltage. If we record 12 V at the engine input, the problem is in the engine. The brushes may be worn out or burnt, the motor commutator may have burned out, or the winding may have burned out or shorted out. In any case, no one will bother with it, we’ll just replace the electric motor with a new one.

Checking the automatic heater control system

The stove control system can also give out surprises. They consist in the fact that one of the speeds may not work, several, or only one, the most powerful, may work. At the same time, the SAUO block is not universal and is selected depending on the year of manufacture of the car:

One of the reasons for the failure of the stove may be the unit of the automatic heater control system.

• 2110-8128020-03, price 2300 rubles, used in the last ten years of production;
• 21102-8121020, price 3100 rubles, installed on cars with air conditioning;
• 2110-8128020-02, about 2 thousand, set for the first ten years of production;
• 2110-8128020-01, 1840 rubles, used on some cars before the year 2000.

The stove is blowing cold air due to problems with the cooling system

A fairly common reason why the stove may blow cold air is neglect of maintenance requirements for the cooling system or its failure. To fix this problem, we need to perform a few fairly simple steps:

• First, we replenish the supply of coolant, adding it to a certain level;
• if this does not help, start the engine and monitor the temperature sensor as it heats up. If it remains at the same level, the thermostat valve may be broken, which should be urgently replaced with a new one;
• the last stage is to check the presence of air in the cooling system, which penetrates into it through the broken cylinder head gasket. This malfunction is usually indicated by such symptoms as a leak of antifreeze, which can splash out of the tank and mix with oil, too high a temperature on a sensor located inside the passenger compartment, and “triple” of the engine.

The last fault can be eliminated by installing a new gasket. It firmly blocks the access of air, and the problem disappears on its own.