Page 1 of 34
19-1
 
     
Cooling system components, 
removing and installing 
     
WARNING! 
     
The cooling system is pressurized when the 
engine is warm. When opening the expansion 
tank, wear gloves and other appropriate 
protection, cover the cap using a cloth, and 
open carefully to relieve system pressure 
slowly. 
     
Note:  
     
Cooling system is under pressure when engine 
is warm. If necessary reduce pressure before 
repair. 
     Secure all hose connections using production-
type clamps   parts catalog. 
     
VAG1921 pliers are recommended for installing 
spring clips. 
     Always replace gaskets, seals and O-rings.
     Arrows on coolant lines and hoses must 
align. 
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19-2
 
  
Cooling system components
 
Coolant hose connection diagram  
1 - 
Heater core 
After replacing, replace coolant
2 - 
Lower coolant line Removing and installing   Page 19
-22
3 - 
Expansion tank 
With capPressure relief valve in cap, checking   
Page 19
-30
 
4 - 
Oil cooler 
Removing and installing   Page 17
-7 , 
item 14 
5 - 
Intake manifold 
6 - 
Lower coolant hose 
7 - 
Upper coolant hose 
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19-3
 
  
8 - 
Radiator 
Removing and installing   Page 19
-24
After replacing, replace coolant
9 - 
Upper coolant line 
10 - 
Coolant pump/coolant thermostat Coolant pump, removing and installing   
Page 19
-13
 
Check for ease of movementCoolant thermostat, removing and installing 
 Page 19
-20
 
Checking  Page 19
-21
11 - 
Turbocharger 
12 - 
Cylinder head/cylinder block 
After replacing, replace coolant
13 - 
Connector 
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        Page 4 of 34
19-4
      
Cooling system, draining and filling
 
     
Special tools and equipment  
     
VAG1306 drip tray
     VAG1274/10 with VAG1274/1 adapter or 
VAG1274/8 
     T40007 refractometer
     
Draining  
     
Note:  
     Drain coolant into a clean container for recycling 
or reuse. 
     
WARNING! 
     
The cooling system is pressurized when the 
engine is warm. When opening the expansion 
tank, wear gloves and other appropriate 
protection, cover the cap using a cloth, and 
open carefully to relieve system pressure 
slowly. 
     
-  Open coolant expansion tank cap.
    
-  Remove noise insulation panel (arrows).
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        Page 5 of 34
19-5
      
-  Place VAG1306 drip tray underneath engine.
     
CAUTION! 
     
Observe disposal regulations for coolant! 
    
Note:   -  Remove retaining clip (arrow) from lower coolant hose and remove 
coolant hose from radiator. 
    
With bumper removed, coolant can be drained through radiator drain plug 
(arrow). 
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        Page 6 of 34
19-6
 
    
Filling  
Note: 
CAUTION!  -  Remove drain plug from coolant pump (arrow).
The cooling system is filled year-round with frost and corrosion 
protection additives. Until 6/96, G 011 A8 C coolant (green color) was used.From 7/96 on, only G 012 A8 D coolant (red color) is used.Coolants G 011 A8 C and G 012 A8 D CANNOT be mixed. Mixing 
them will cause severe engine damage. Part numbers are for reference only. Always check with your Parts 
department for the latest information. If the fluid in the expansion tank is brown, G012 A8 D has been mixed 
with other coolant. In this case, flush cooling system and change 
coolant. To flush, fill cooling system with clear water and run engine 
for approx. 2 minutes. Flushing the system should remove most of the 
coolant residue. 
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        Page 7 of 34

19-7
      
Note (continued from page   Page 19
-6 ):  
     
G 011 A8 C or G 012 A8 D and coolant 
additives marked with "according to TL VW 
774C" or "according to TL VW 774 D", prevent 
frost and corrosion damage as well as calcium 
deposits. They also raise the boiling point. 
Therefore, cooling system must be filled year-
round with frost and corrosion protection 
additives. 
     A higher boiling point improves engine reliability 
under heavy load, particularly in countries with 
tropical climates. 
     Frost protection additives must protect against 
frost to about -25 C (-13 F) and to about -35
C (-31 F) in arctic climates. 
     
The coolant concentration must not be reduced 
by adding water even in warmer seasons and in 
warmer countries. The anti-freeze ratio must be 
at least 40%. 
     If for climatic reasons greater frost protection is 
required, the amount of G 011 A8 C or G 012 
A8 D can be increased, but only up to 60% to 
obtain frost protection to about -40 C (-40 F). 
Otherwise frost protection and cooling 
effectiveness will be reduced. 
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        Page 8 of 34
     
If the radiator, heater core, cylinder head or 
cylinder head gasket is replaced, completely 
replace the engine coolant. 
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