Why does the stove in the car heat up badly and how to deal with it

2024 Author: Malcolm Clapton | [email protected]. Last modified: 2023-12-17 03:44

If the cabin is cold, the windows sweat, and in the morning it takes a lot of time to defrost them, it's time to act.

There are many reasons why the stove does not heat well. Let's start with the most common ones.

1. Low coolant level or air lock

Due to leaks at the joints of the pipes or on the radiator, the coolant level in the system may decrease. This will worsen its circulation inside the heater radiator and affect its warming up. Air locks that form when replacing or adding antifreeze have the same effect.

What to do

Check the coolant level and top up if necessary. If there are leaks, fix them.

To get rid of the plug, open the cap on the expansion tank and radiator (if equipped), and then squeeze any thick hoses you can reach with your hand several times.

Start the engine, turn on the stove to maximum and let the car idle until it warms up completely. To be sure, it would be good to drive onto an overpass or some kind of hill to raise the front of the car and help the air escape. A small amount of antifreeze may splash out - be careful.

2. Clogged cabin filter and air duct

Sometimes the reason for a poorly working heater can be a dirty cabin filter or leaves, insects and dust that have gotten into the air duct due to its absence. In this case, the radiator itself warms up, but cannot give off heat due to the weak air flow.

What to do

Check the cabin filter and replace if necessary. If there is no filter at all, although it should be, then clean the air duct from debris. If possible, get to the heater radiator itself and blow it well with compressed air.

3. Faulty thermostat

This is a common cause of stove problems. If the thermostat wedges in the closed position, then the breakdown is noticed immediately, since in this case the engine overheats. But if we are talking about an open or slightly open position, then, as a rule, drivers find out about this only with the onset of cold weather.

If the thermostat is constantly open, the coolant always flows in a large circle. As a result, the engine takes a very long time to warm up, and sometimes it does not completely warm up at all. Of course, there can be no question of any normal operation of the heater. This increases fuel consumption, and in the case of an automatic transmission, its warm-up time also slows down.

Signs of a faulty thermostat are more or less tolerable heating of the stove when driving at a low speed and cold air from the ventilation when driving on the highway. The fact that the thermostat is constantly open is also indicated by the simultaneous heating of both radiator hoses. Normally, when starting the engine, one of them should be warm, and the second should be cold.

What to do

There is only one option: replace the thermostat with a new one.

4. Heater radiator clogging

Another common reason. Typically, blockages occur due to poor quality coolant, mixing different liquids, adding water or using sealants for the cooling system. Deposits and scale that form inside the radiator completely clog the honeycomb and block the circulation of antifreeze.

What to do

Removing and changing a radiator can be tricky on any car, so try flushing it first. You will need a special product or ordinary citric acid (100 grams must be dissolved in 5 liters of distilled water). Standard hoses are removed from the radiator, others are connected to the inlet and outlet. The liquid is heated to 80–90 ° C and supplied to the radiator using a pump.

Unfortunately, flushing is not a panacea. It helps about half the time. In addition, leaks can form due to washing away of internal deposits.

If flushing does not work, only replacing the radiator will help. In this case, it will also be useful to completely flush the entire cooling system and replace the fluid.

5. Wear of the pump impeller

A pump is a pump that pumps antifreeze from the engine, ensuring its continuous circulation throughout all components of the cooling system. It is quite difficult not to notice a breakdown of the pump: in this case, the engine will immediately overheat and boil.

When the impeller blades are worn out due to the aggressive effects of water or poor-quality antifreeze, the pump performance drops significantly. It is still enough for the coolant to somehow circulate and the engine does not overheat, but it is not enough to fully warm up the heater radiator.

What to do

As a rule, pumps are not repaired. Therefore, the problem is solved by replacing the faulty unit with a new one.

6. Fan problems

The cold in the cabin can be caused not only by insufficient heating of the heater radiator, but also by its weak blowing. This is already the fault of the fan, which does not provide the necessary air flow and heat dissipation from the radiator.

What to do

If the fan does not work at all, then everything is clear. More often than not, it rotates, but with insufficient speed. This is due to wear on the brushes of the electric motor or wedging of the bearings. In both cases, repairs by an auto electrician will be required.

7. Breakage of the damper servo

Another reason why the stove heats up, but the heat does not reach the salon, is a malfunction in the damper operation. In all modern cars, the heater radiator heats up constantly, and heat from it comes only when the air duct damper is open. If the damper does not open or does not open completely, there can be no question of the optimal temperature.

The damper is driven by a servo, which is controlled by a knob or buttons on the climate control panel. The problem can be both in the breakdown of the servo itself, and in the slipping of the cables or rods that set the damper in motion.

What to do

It is possible to identify and correct this problem only when disassembling the heater panel. If the rods or cables have come off, they must be returned to their place. A malfunction of the servo, unless it has completely failed, can only be diagnosed by a specialist. Servos are rarely repaired, basically the problem is solved by replacing them with a new one.

8. Breakdown of the heater control unit

In addition, the air damper may not open due to malfunctions in the climate control unit or temperature sensors. In this case, the required signal is simply not supplied to the drive, which, in turn, does not open the damper, and cold air flows into the cabin instead of hot air.

What to do

Only a specialist after disassembly and diagnostics can determine the exact cause of the breakdown. Therefore, you will hardly be able to do without a trip to a good car service.

9. Leakage of the heater body and displacement of the radiator

A rather rare problem is a leakage of the case. After an accident or improper assembly, the plastic parts of the stove may be damaged or have gaps through which hot air will escape. In this case, the efficiency of the heater will be significantly reduced.

In some cars, due to weak latches or other design flaws, the radiator may move from its place, and the air blown by the fan will not pass through it, but by. The same thing happens when the air duct damper is closed, that is, there is no need to talk about any heat.

What to do

In both cases, it is necessary to disassemble the dashboard in order to get to the heater and restore its normal operation. That is, fix the damage, seal the joints of the housing parts, put the heater radiator back in place and fix it well.

You can cope with this on your own, but the work is not easy. Therefore, if you are not confident in your abilities, contact the specialists.

10. Breakdown of the cylinder head gasket

The most annoying problem, which, fortunately, is quite rare. Due to engine overheating and poor tightening of the cylinder head, the gasket under it can be damaged at some point. If a breakdown occurs between the cooling jacket and the combustion chamber, the gases from it will enter the antifreeze, forming bubbles and impairing circulation, and in some cases even creating air locks.

You can recognize the breakdown of the gasket by the thick white smoke, or rather, the steam from the muffler, which is formed from the ingress of coolant into the cylinder. At the same time, air will boil in the expansion tank, and due to the increased pressure, boiling off and even splashing out of antifreeze is possible.

What to do

You shouldn't joke about it. At the slightest suspicion of a breakdown of the cylinder head gasket, it is better to immediately contact the minders. If the problem is not resolved in a timely manner, it can result in more serious malfunctions and costly engine repairs.