Engine-Side Coolant System Components - Overview

WARNING: This page is about a different car, the 2014 Volkswagen Jetta, 2013 Volkswagen Jetta, 2012 Volkswagen Jetta, and 2011 Volkswagen Jetta. However, it is still accessible from the selected car via links, so may be relevant.

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