Mechanical Diagrams

Coolant Hose Connection Diagram

Risk of scalding due to hot steam and hot coolant.

• The coolant system is under pressure when the engine is warm.

• Reduce pressure by covering coolant reservoir cap with a cloth and carefully opening.

• When the engine is warm the cooling system is under pressure. If necessary release pressure before commencing repair work.

• Secure all hose connections using hose clamps appropriate for the model type. Refer to the Parts Catalog.

• The hose clip pliers (V.A.G 1921) or hose clip pliers (VAS 6340) are recommended for installing spring clamps.

• Always replace gaskets and seals.

• Arrows on coolant pipes and coolant hoses must line up across from each other.

• Blue = large coolant circuit.

• Red = small coolant circuit.

• Brown = heating circuit.






1 Radiator

• Change coolant after replacing

2 Turbocharger

3 Cylinder Head/Cylinder Block

• Change coolant after replacing

4 Coolant Switch-Off Valve

• Controlled by a vacuum from the Climatronic refrigerant shut-off valve (N422)

• Removing and installing,

5 Bleeder Hole

6 Heat Exchanger for Heater Unit

• Change coolant after replacing

7 Coolant Pump (V50)

• Installed only on vehicles with a start/stop system

8 Coolant Pump

• Removing and installing, refer to => [ Coolant Pump ] Coolant Pump

9 Restrictor

10 Coolant Reservoir Cap

• Pressure relief valve, checking => [ Pressure Relief Valve In Cap, Checking ] Testing and Inspection

11 Coolant Reservoir

12 Check Valve

13 After-Run Coolant Pump (V51)

• Installed only on hot climate vehicles

14 Coolant Thermostat

15 Engine Coolant Temperature (ECT) Sensor (G62)

• Removing and installing, refer to => [ Engine Coolant Temperature Sensor (G62) ] Service and Repair

16 Engine Oil Cooler