Engine-Side Coolant System Components - Overview

NOTE:

Coolant Hose Connection Diagram, refer to COOLANT HOSE CONNECTION DIAGRAM .

Vehicles with an automatic transmission have a by-pass thermostat in the coolant supply hose to the transmission fluid cooler.

Bypass thermostat - overview, refer to Fig 2.

Bypass thermostat, checking, refer to Fig 2.

Fig 1: Identifying Engine-Side Coolant System Components Overview

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

To Top of Coolant Reservoir
Coolant Connections on Heater Core
O-Ring
- Replace
Connector
- For Engine Coolant Temperature Sensor -G62-
- 2-pin
Engine Coolant Temperature Sensor -G 62-
Clip
- Make sure it is secure
From Transmission Oil Cooler
- Only vehicles with automatic transmission
Bolt
- 40 Nm
Coolant Pipe
Bolt
- 9 Nm
O-Ring
- Replace
Coolant Distribution Housing
To Transmission Fluid Cooler
- Only vehicles with automatic transmission
From Bottom of Reservoir
Preheater
- Not installed on all vehicles
- Overview, refer to OVERVIEW - ENGINE PRE-HEATER .
To Upper Radiator Connection
To Upper Radiator Connection
From Lower Radiator Connection
Engine Oil Cooler
Bolt
- 15 Nm
Connection
Coolant Thermostat
- Checking: Heat up thermostat in water
  Starts to open: approximately 86 °C (186.8 °F)
  
  Opening lift: minimum 7 mm
- Removing and installing, refer to COOLANT THERMOSTAT, REMOVING AND INSTALLING .
Toothed Belt
- Mark direction of rotation before removing
- Check for wear
- Do not kink
- Removing and installing, refer to TOOTHED BELT, REMOVING AND INSTALLING .
Coolant Pump
- Check for ease of movement
- Replace completely if damaged or leaking
- Removing and installing, refer to COOLANT PUMP, REMOVING AND INSTALLING .
Bolt
- 15 Nm
Rear Toothed Belt Guard
Bolt
- 20 Nm
Throttle Valve Control Module -J338-

Fig 2: Identifying Bypass Thermostat Assembly Overview

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

1 -

Spring Bracket

2 -

Housing Lower Section

Note installation position: The arrow points to ATF cooler

3 -

Operating Element

4 -

Spring

5 -

O-ring

6 -

Housing Upper Section

Checking Bypass Thermostat

-- Remove the operating element -3- and warm it up in hot water.

Opening begins: approximately 75 °C (167 °F)

Opening ends: approximately 85 °C (185 °F)

Opening travel: approximately 5 mm