A4 Mk3
| Diagram of coolant hose connections |
| Vehicles without auxiliary heater |
Note| t | Blue = Large coolant circuit. |
| t | Red = Small coolant circuit. |
| t | Brown = Heating circuit. |
| t | Orange = Coolant circuit for exhaust gas recirculation. |
| 1 - | Not fitted |
| 2 - | Radiator |
| q | If renewed, refill system with fresh coolant |
| 3 - | Coolant pump |
| 4 - | Cylinder head/cylinder block |
| q | If renewed, refill system with fresh coolant |
| 5 - | Exhaust gas recirculation cooler |
| q | If renewed, refill system with fresh coolant |
| 6 - | Exhaust gas recirculation temperature sensor -G98- |
| 7 - | Coolant temperature sender -G62- |
| 8 - | Coolant circulation pump -V50- |
| q | On vehicles with start/stop system only |
| 9 - | Coolant shut-off valve |
| q | Activated by Climatronic coolant shut-off valve -N422- (negative pressure) |
| q | Removing and installing → Rep. gr.87 |
| 10 - | Bleeder hole |
| 11 - | Heat exchanger for heater |
| q | If renewed, refill system with fresh coolant |
| 12 - | Thermostat |
| q | For exhaust gas recirculation cooler |
| 13 - | Non-return valve |
| q | Arrow points in direction of through-flow |
| 14 - | Sealing cap |
| q | For coolant expansion tank |
| q | Checking → Chapter |
| 15 - | Coolant expansion tank |
| q | Checking cooling system for leaks → Chapter |
| 16 - | Engine oil cooler |
| q | If renewed, refill system with fresh coolant |
| 17 - | Pump for exhaust gas recirculation cooler -V400- |
| 18 - | 4/2-way valve with thermostat |
| Vehicles with auxiliary heater |
Note| t | Blue = Large coolant circuit. |
| t | Red = Small coolant circuit. |
| t | Brown = Heating circuit. |
| t | Orange = Coolant circuit for exhaust gas recirculation. |
| 1 - | Not fitted |
| 2 - | Radiator |
| q | If renewed, refill system with fresh coolant |
| 3 - | Coolant pump |
| 4 - | Cylinder head/cylinder block |
| q | If renewed, refill system with fresh coolant |
| 5 - | Exhaust gas recirculation cooler |
| q | If renewed, refill system with fresh coolant |
| 6 - | Exhaust gas recirculation temperature sensor -G98- |
| 7 - | Coolant temperature sender -G62- |
| 8 - | Auxiliary heater |
| q | On vehicles with start/stop system only |
| 9 - | Bleeder hole |
| 10 - | Heat exchanger for heater |
| q | If renewed, refill system with fresh coolant |
| 11 - | Heater coolant shut-off valve -N279- |
| q | Diagram of connections, removing and installing → Rep. gr.87 |
| 12 - | Thermostat |
| q | For exhaust gas recirculation cooler |
| 13 - | Non-return valve |
| q | Arrow points in direction of through-flow |
| 14 - | Sealing cap |
| q | For coolant expansion tank |
| q | Checking → Chapter |
| 15 - | Coolant expansion tank |
| q | Checking cooling system for leaks → Chapter |
| 16 - | Engine oil cooler |
| q | If renewed, refill system with fresh coolant |
| 17 - | Pump for exhaust gas recirculation cooler -V400- |
| 18 - | 4/2-way valve with thermostat |