Thermostat: Service and Repair
Thermostat Removing and Installing
Note:
Refer below, to both "Cooling System, Engine Side" and "Thermostat Housing, Disassembling and Assembling" information for thermostat service.
Cooling System, Engine Side
1. Pressure cap
- Check with V.A.G 1274 test instrument and V.A.G 1274/9 adapter
- Test pressure 1.4 - 1.6 bar (20 to 23 psi)
2. O-Ring - Replace if damaged
3. Coolant recovery bottle
- Check for leaks in cooling system using V.A.G 1274 test instrument and V.A.G1274/8 adapter
4. Bolt. Torque Specification: 10 Nm (7 ft. lbs.)
5. Upper coolant pipe - Clipped into the bulkhead
6. To heat exchanger
7. Throttle valve control unit (J338) - Heated by coolant
8. To upper coolant hose
9. To upper radiator
10. Gasket - Replace
11. To lower radiator
12. Thermostat housing
13. Coolant feed pump (V51) - Check
14. From heat exchanger
15. Bolt. Torque Specification: 25 Nm (18 ft. lbs.)
16. Oil cooler
- Coat contact surfaces outside of sealing ring with AMV 188 001 02
- Ensure free movement among surrounding components
17. Screw plug
18. Coolant pipe
19. Coolant pump - Observe installation position
- Check for smooth running
- Replace completely if damaged or if leaking
20. Bolt. Torque Specification: 15 Nm (11 ft. lbs.)
21. Pulley for coolant pump
22. 25 Nm (18 ft. lbs.)
23. To Y-branch of heat exchanger/coolant feed pump Coolant hoses, connection diagram
Thermostat Housing, Disassembling and Assembling
Note:
Routing of hoses at the coolant controller housing.
Exploded View
1. Plug
2. O-Ring
- Always replace
3. Gasket
- Always replace
4. Retaining clamp
- Check for tight fit
5. Thermostat housing
6. Bolts. Torque Specification: 10 Nm (7 ft.lbs.)
7. Thermostat
Install position: large plate downward
Checking: heat controller in water bath
Opening starts at approx. 80°C
Opening ends at approx. 105°C
Travel at least 7 mm
8. Connector
9. Bolts. Torque Specification: 10 Nm (7 ft. lbs.)
10. Coolant temperature sensor (G62)
- With coolant temperature display sensor (G2)
- For engine control module
- If necessary, release pressure from cooling system before removing