Table of Contents > Descriptions of work > Cooling system: checking frost protection and coolant level

VW Passat B7 Service Manual ➜ Cooling system: checking frost protection and coolant level

Passat 2011 ➤ , Passat Variant 2011 ➤  
Maintenance - Edition 01.2019  
Cooling system: checking frost protec‐  
tion and coolant level  
The water used for mixing has a major influence on the effec‐  
tiveness of the coolant. Because the water quality differs from  
country to country and even from region to region, the quality  
of the water to be used in the cooling system has been speci‐  
fied by Volkswagen. Distilled water fulfils all requirements.  
Therefore, only ever use distilled water when mixing coolant  
for topping up or renewing coolant.  
Use only coolant additives which conform with the ⇒ Elec‐  
tronic parts catalogue (ETKA) . Other coolant additives may  
reduce corrosion protection substantially. The resulting dam‐  
age could lead to loss of coolant and subsequent severe  
damage to the motor.  
Mixed in the proper proportions, coolant inhibits frost and cor‐  
rosion damage as well as scaling. Furthermore, the boiling  
point is raised. For these reasons, the cooling system must be  
filled all year round with a coolant additive.  
Because of its high boiling point, the coolant improves engine  
reliability under heavy loads, particularly in countries with trop‐  
ical climates.  
Use ONLY refractometer - T10007A- for determining current  
anti-freeze value.  
Frost protection must be guaranteed down to -25°C as a min‐  
imum and, in countries with arctic conditions, down to approx.  
-36°C. Increasing the frost protection is permissible only if cli‐  
matic conditions require stronger frost protection. It may, how‐  
ever, be increased only to a maximum of -48°C. Otherwise,  
the cooling effect will be impaired.  
Do not reduce the coolant concentration by adding water even  
in the warm season or in hot countries. Frost protection must  
be guaranteed down to at least -25°C.  
Read anti-freeze figures from the respective scale for type of  
anti-freeze added.  
The temperature read off the refractometer - T10007A- corre‐  
sponds the »ice flocculation point«. Flakes of ice may start  
forming in the coolant at this temperature.  
Never reuse old coolant.  
Use only a water/coolant additive mixture as a slip agent for  
coolant hoses.  
Frost protection: checking, replenishing  
coolant additive if necessary  
Special tools and workshop equipment required  
4. Descriptions of work:  
Passat 2011 ➤ , Passat Variant 2011 ➤  
Maintenance - Edition 01.2019  
♦ Refractometer - T10007 A-  
Read precise value for the following tests at light/dark boundary.  
Using a pipette, place a drop of water on the glass to improve the  
readability of the light/dark boundary. The light-dark border can  
be clearly recognised on the “WATERLINE”.  
– Check concentration of coolant additive using refractometer -  
T10007 A- (refer to operating instructions).  
The scale -1- of the refractometer is calibrated for coolant addi‐  
tives G12; G12 Plus, G12 Plus Plus and G11.  
The scale -2- is only calibrated for coolant additive G13.  
– If frost protection is insufficient, drain coolant and supplement  
coolant additive ⇒ page 96 .  
If the currently used coolant additive cannot be determined  
precisely, use the scale -2- for coolant additive G13.  
Please observe disposal instructions!  
– Check coolant additive concentration after road test again.  
Coolant level: checking, replenishing  
coolant if necessary  
– Check coolant level in expansion tank when engine is cold.  
♦ Delivery inspection: coolant level above “min” marking  
♦ Inspection service: coolant level above “min” marking  
– If coolant is too low, add required amount according to mixture  
If fluid loss is greater than can be expected through normal use,  
determine source and rectify (repair measure).  
4. Descriptions of work:  
Passat 2011 ➤ , Passat Variant 2011 ➤  
Maintenance - Edition 01.2019  
Mixing ratio:  
Use only distilled water for mixing coolant additives. The use  
of distilled water ensures optimum protection against corro‐  
Frost protection to  
Coolant additive  
Distilled water  
-25 °C  
-36 °C  
approx. 40%  
approx. 50 %  
approx. 60 %  
approx. 50 %  
Diesel fuel filter: renewing  
Special tools and workshop equipment required  
♦ Diesel extractor - VAS 5226-  
♦ Angled screwdriver - VAS 6543-  
♦ Ensure that no diesel fuel contacts other components in  
the engine compartment. Clean immediately, if necessa‐  
Remove engine cover panel ⇒ page 106 .  
4. Descriptions of work:  

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