Operation CHARM: Car repair manuals for everyone.

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