Coolant Pump and Thermostat Overview
Coolant Pump and Thermostat Overview
When doing any repair work, especially in the engine compartment, pay attention to the following due to clearance issues:
• Route all lines and wires in their original locations.
• Make sure there is enough clearance to moving or hot components to prevent damage to the lines.
• When the engine is warm the cooling system is under pressure. If necessary release the pressure before beginning any repair work.
• Secure all hose connections with clamps, allocation, refer to the Parts Catalog.
• The hose clip pliers (V.A.G 1921) or (VAS 6362) are recommended for installing spring clamps.
• Always replace gaskets and seals.
• The arrows on coolant pipes and coolant hoses must line up across from each other.
Part 1: Belt Pulley Side
Part 2: transmission side
1 Cylinder Block
2 Engine Oil Cooler
3 Bolt
• 25 Nm
4 Bolt/Nut
• 10 Nm
5 to the Heater Core Lower Connection
6 Retaining Clip
7 O-ring
• Always replace.
8 Front Coolant Pipe
9 Connecting Hose
10 O-ring
• Always replace.
11 Coolant Pipe
12 Connecting Hose
13 Cover
14 to the Radiator Lower Connection
15 Bolt
• 5 Nm
16 O-ring
• Always replace.
17 Coolant Thermostat
• Removing and installing, refer to => [ Coolant Thermostat ] Coolant Thermostat.
• Note the installed position: the valve must be at the top.
• Checking (coolant thermostat installed): Refer to the "Function and Component Selection" in the vehicle diagnostic tester.
• Checking (coolant thermostat removed):
Heat the thermostat in water.
Starts to open: approximately 87 °C (188.6 °F) Opening ends: approximately 102 °C (215.6 °F) Open distance: at least 7 mm
18 Seal
• Always replace.
19 Bolt
• 25 Nm
20 Coolant Thermostat Housing
21 Seal
• Always replace.
22 Accessory Bracket
23 Bolt
• 10 Nm
24 Coolant Pump
• With an integrated silicone seal for sealing to the cylinder block.
• Removing and installing, refer to => [ Coolant Pump ] Service and Repair.
25 Right Coolant Pipe
• Secured to the engine mount.
26 to the Expansion Tank Lower Connection
Part 2: Transmission Side
1 Coolant Connection
• Pressed in the cylinder head.
• Clean before installing the coolant flange - item 17 -
- If necessary, remove any coolant deposits with a brass wire brush or with a fine sandpaper (minimum 100 grit).
• If the pipe connection is worn, replace it using liquid locking fluid (D 000 600 A2).
2 Thrust Ring
3 Seal
• Replace after removing the coolant flange - item 17 -.
4 to the Expansion Tank Upper Connection
5 Rear Coolant Pipe
6 Bolt/Nut
• 10 Nm
7 Heat Shield
8 to the Heater Core Upper Connection
9 Supply Hose
10 Bypass Thermostat
• Only for vehicles with a automatic transmission.
• Overview, refer to => [ Bypass Thermostat Overview ].
11 to the Automatic Transmission Fluid Cooler
• Only for vehicles with a automatic transmission.
12 to the Heater Core Lower Connection
13 from the Automatic Transmission Fluid Cooler
• Only for vehicles with a automatic transmission.
14 Return Hose
15 Coolant Pipe
• Bolted to the coolant flange - item 17 -
16 to the Coolant Thermostat Housing
17 Flange
18 Supply Hose
19 to the Radiator Upper Connection
20 Coolant Hoses
• Only for a throttle valve control module heated by coolant.
21 Throttle Valve Control Module (J338)
22 Engine Coolant Temperature Sensor (G62)
23 O-ring
• Always replace.
24 Retaining Clip
Bypass Thermostat Overview
1 Spring bracket
2 Lower part of housing
Note the installed position: The arrow points toward the automatic transmission fluid cooler
3 Operating element
4 Spring
5 O-ring
6 Upper part of housing
Checking the Bypass Thermostat:
- Remove the operating element - 3 - and heat in a hot water bath.
Starts to open: approximately 75 °C (167 °F)
Stops at: approximately 85 °C (185 °F)
Opening lift: approximately 5 mm