If the engine in the car does not warm up! The reasons.

Recently updated on January 27, 2022 at 10:34 am

Why the engine in the car does not get warm can have many backgrounds. In order to find out the exact cause, a distinction must be made as to whether just the engine not getting warm, whether the heater is on but stays cold, or both. A motor needs a certain amount of time before it finds the right one Operating temperature achieved, that must not be forgotten. In winter, it is therefore not uncommon for a diesel vehicle to take a few kilometers to reach the right temperature in the engine and interior. It's not uncommon for the engine to heat up badly, especially when there's hardly any uphill or even only downhill right from the start.

many causes and solutions

No matter what problem arises, it should be this in the first place Reading the error memory stand. Three problems can arise here. If the engine reaches its operating temperature, but the interior remains cold, then it stands to reason that the Heating has a technical or mechanical problem. More on that below. Does the heater get warm, but the engine temperature gauge in the cockpit shows no reaction, either the display in the cockpit or the coolant temperature sensor is defective. Should neither the engine nor the interior get warm, then the cooling circuit should be checked. In most cases it's because of one defective thermostat.

What time is normal before the engine has to be at operating temperature?

What temperature the Motor respectively that cooling water haen, can be seen in the cockpit on the temperature display (if available) can be read. When the correct operating temperature has been reached, the pointer on the temperature gauge will stand still in most cases center, i.e. vertical. Gasoline engines, also known as Otto engines, should cool down during the summer about 10 and in winter after about 15 kilometers achieved. It often takes longer with a diesel engine.

A diesel normally needs 10 to 15 kilometers in the summer before it has reached the right operating temperature. In winter it looks different. In city traffic it sometimes happens that a modern diesel does not reach its operating temperature for a long time. This does not necessarily indicate a defect. The newer engines, for example from the VAG group (1.6 TDI/2.0 TDI) often have high efficiency. This means they mostly reach their optimum operating temperature in cold weather only under high load. This could be driving on the freeway, for example. At a speed of around 130 km/h, the correct temperature should be reached after around 10 kilometers of driving, even with these engines.

possible causes if the car does not get a temperature

Defective interior blower motor

If the vehicle's engine reaches its operating temperature but the interior remains cold, a defective Interior blower motor be the cause. The interior fan motor is responsible for ensuring that the air heated by the heat exchanger reaches the vehicle interior. If the motor is the cause, then it must be replaced together with the series resistor provided for this purpose. Occasionally only one cares Fuse, which has a defect, for the problem. If the blower only runs at the highest level, the Series resistor malfunction. Not only should the series resistor be changed, but the cause of the defect should also be sought. In many cases, the interior fan motor is defective.

Radiator Fan - Fan motor is on continuously

If a radiator fan running continuously, this causes excessive cooling. This may be due to a defective viscous coupling. If an electric fan is installed, a defect on the Coolant temperature sensor, which returns an incorrect value, let the fan run continuously and cool. In this case, either the coolant temperature sensor or the viscous coupling must be replaced. However, that depends on the exact cause. If the fan motor has a defect, which can occur, for example, due to incorrect control or a short circuit, then the fan must be replaced.

Defect in the servomotor of the temperature flaps

How much warm air gets to the interior fan is regulated in modern cars by the so-called temperature flaps. Is there one defective servomotor installed, this can ensure that the heating stays cold. This is then usually stored in the error memory. A defective fuse can also cause the failure. Incidentally, in some vehicles, the dashboard has to be removed for the change, which causes a lot of work.

clogged heat exchanger

The task of the heat exchanger is to heat the air before it enters the interior of the vehicle. Heated cooling water from the engine flows through it. If the heat exchanger is clogged, which can come from a radiator sealant, for example, then it may be that the incoming air is no longer sufficiently heated. Which leads to the interior stays cold, although the heating is switched on. But that could also be a reason Cooling water valve be in front of the heat exchanger if it shows a defect. The heat exchanger is often difficult to reach, which is why the dashboard may have to be removed for a change. Also the air conditioning circuit must be partially opened.

Faulty thermostat

Should neither the engine nor the interior get warm, then the cooling circuit should be checked. In most cases it's because of one defective thermostat. The thermostat is responsible for separating the two cooling water circuits from each other. When the engine is cold, the cooling water only circulates in a small circuit so that the engine reaches the correct operating temperature as quickly as possible. If the thermostat is defective, there is a possibility that it will remain open all the time. This ensures that the cooling water only circulates through the large cooling circuit and cooler and keeps the small circuit closed. The engine can thus reach the correct operating temperature not reach, since it is permanently cooled down. As a result, the heater also stays cold because no warm air can reach it. In this case, the thermostat must be replaced with a new one. It is advisable to change the cooling water as well.

defective interior temperature sensor

The interior heating in newer cars is controlled by a lot of electronics. It's about an additional designated Controller installed, which relies on the readings from the interior temperature sensor. However, if this does not deliver any or incorrect values ​​due to a defect, it is not possible to regulate the temperature in the interior correctly. If that is the cause, the sensor must be replaced.

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