Servicing additional water heater -D3W- — VW

Warning!
Always disconnect the battery earth strap before working on the electrical system.
Note:

Before disconnecting battery obtain radio anti-theft coding.
A manufacturer's plate is attached to the heater unit. This plate gives details of heater unit type installed in vehicle
=> Fig.
1
.
Removing and installing heater unit components => Page
82-175
; dismantling and assembling heater unit -D3W-.

After working on coolant circuit check coolant circuit

=> 5-Cyl. Diesel engine, Mechanics; Repair group 19
5-Cyl. Diesel engine, Mechanics

Ambient temperature switch -F38-
Switch position -On-
at temperatures lower than 5 °C
Switch position -Off-
at temperatures above 5 °C
Removing => Fig.
2

Fuel pump -G23-
Removing and installing
=> Page
82-238
; water heater fuel supply

Exhaust system
Removing and installing => Fig.
6
Securing exhaust pipe to heater unit => Fig.
4

Heater unit
With control unit -J162-
Removing => Fig.
5
Dismantling and assembling =>Page
82-175

Coolant hoses
Coolant hose routing => Page
82-227
; connecting water heater into coolant circuit

Fig.1
Manufacturer's plate

Notes:

Only D3W version 25 1864 01 is installed during manufacture in Transporter 1991▸ .
The relevant technical data are shown on upper part of manufacturer's plate.
The date first taken into use is on the lower part of manufacturer's plate.

Fig.2
Removing ambient temperature switch -F38-

Unclip ambient temperature switch -1- from bracket.
Checking ambient temperature switch:

=> Fault finding; Heating, air conditioning binder 2

Fig.3
Removing and installing exhaust system

1 -
Silencer
2 -
Pop rivet
3 -
Silencer bracket
4 -
Hose clamp
5 -
Self-tapping screw
6 -
Exhaust pipe to heater unit
7 -
Clip
8 -
Self-tapping screw

Notes:

The exhaust pipe -6- is to be routed so as not to touch the wiring (danger of short circuit). Further notes => Fig.
4
.
On vehicles with foglights the exhaust pipe must be a distance of at least 20 mm from the foglight.

Fig.4
Securing exhaust pipe to heater unit

The exhaust pipe -1- is pushed in direction of arrow until it contacts the combustion air blower housing -2-.

Fig.5
Removing and installing heater unit

1 -
Intake hose
2 -
Screw type clamp
3 -
Screw type clamp (5 Nm)
4 -
Exhaust pipe to silencer
5 -
Heater unit
6 -
Bonded rubber mounting (8 Nm)
7 -
Bracket
8 -
Wire hook
9 -
Hexagon nut (8 Nm)
10 -
Hexagon bolt (8 Nm)
11 -
Bracket
12 -
Rubber buffer

13 -
Retainer
14 -
Fuel pipe retainer
15 -
Fuel pipes

Removing

Removing radiator grille:

=> General body repairs; Repair group 66; Servicing radiator grille; Removing radiator grille
General body repairs
Servicing radiator grille
Removing radiator grille

Fold radiator and lock carrier out forwards.
Remove insulation tray.
Open radiator cap.
Clamp coolant hoses at heater unit.
Pull 8 pin connector off.
Disconnect exhaust pipe at heater unit.
Disconnect fuel pipe at heater unit and seal.
Loosen clamping cap and remove wire hook.
Remove heater from bracket.

Installing

Install in reverse order, to do this note the following:
After installing bleed coolant circuit.

=> 5-Cyl. Diesel engine, Mechanics; Repair group 19
5-Cyl. Diesel engine, Mechanics

Connecting exhaust pipe to heater unit
=>Page
82-172
; Fig.
4