Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Heat exchanger
In order to heat the air in the passenger compartment, the heating system uses the heat that is generated by the engine. The heat exchanger is connected to the cooling system for the engine. The outlet connection for the heat exchanger is located directly on the engine at the point where the pressure and temperature of the coolant are highest. The coolant flows through the cooling ducts for the engine block and on into the heat exchanger. The return flow is connected to the return pipe on the suction side of the water pump.
The heat exchanger comprises a pipe loop through which the engine coolant flows. The pipe has flanges that provide heat to the airflow.
Engine coolant constantly flows through the heat exchanger. There is no valve to regulate the flow. The selected temperature is achieved using dampers for the right and left-hand sides of the car installed upstream of the heater element. These control the amount of air to be warmed. There is also a damper after the heater element which guides air out into the passenger compartment through the various vents.
Vehicles with engine B8444S have an electric pump in the coolant circuit to ensure a comfortable level of heating is supplied to the passenger compartment. The electric pump increases the amount of coolant the flows through the heat exchanger. The pump is located in the engine compartment within the front fender in front of the front left wheel housing.
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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