Automatic heating of intake air (BMW 5 Series E12)

BMW "528", "525", "520"

A heating flap is installed in the intake pipe of the intake silencer, controlled by a thermostatic element due to thermal expansion.

Every 15,000 km, check the ease of movement of the valve and, if necessary, lubricate the hinge joints with oil.

When the valve is closed, the carburetor is fed with air heated by the heat of the exhaust manifold. When the ambient air temperature is about 25*C, the valve opens and closes the heated air supply channel.

BMW "518"

To the right of the radiator, in a special housing, there is an automatic air heating valve, controlled by a lever, which is installed outside the housing and which is set to one of the following two positions:

• position "W" ("Winter"): the air coming through the front of the car is mixed with warm air, heated (to about +30°C) by the heat of the exhaust manifold in a ratio that depends on the ambient air temperature and the engine temperature. At an ambient air temperature of about +30°C, the heated air supply channel is completely closed, and the unheated air channel opens.
• in warm weather (at temperatures above +10°C), set the outer valve lever to position "S" ("Summer").

The valve body cover is secured with a screw.

Every 15,000 km, check the ease of movement of the valve in the "W" position of the lever and, if necessary, lubricate the hinge joints.