Passat 2015 ➤, Passat 2019 ➤, Passat Variant 2015 ➤, Passat Variant 2019 ➤
Maintenance - Edition 11.2020
4.30
Cooling system for high-voltage sys‐
tem: checking coolant additive and
coolant level
Note
♦ The water used for mixing has a major influence on the ef‐
fectiveness 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 specified by Volkswagen. Distilled water satisfies 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
corrosion damage as well as scaling. Such additives also
raise the boiling point of the coolant. For this reason, the
cooling system must be filled all-year-round with coolant ad‐
ditives.
♦ Because of its high boiling point, the coolant improves en‐
gine reliability under heavy loads, particularly in countries
with tropical climates.
♦ The refractometer -T10007A- or refractometer -T10007B-
must be used to determine the current anti-freeze value.
♦ Scale -1- of the refractometer is calibrated for the coolant
additives G12++ and G12evo.
♦ Scale -2- of the refractometer is calibrated for the coolant
additive G13.
♦ If it is not possible to ensure that the same type of coolant
additive is filled: always determine anti-freeze protection us‐
ing the scale for G13.
♦ Frost protection must be guaranteed down to -25°C as a
minimum and, in countries with arctic conditions, down to
approx. -36°C. Increasing the frost protection is permissible
only if climatic conditions require stronger frost protection. It
94
4. Descriptions of work
Passat 2015 ➤, Passat 2019 ➤, Passat Variant 2015 ➤, Passat Variant 2019 ➤
Maintenance - Edition 11.2020
may, however, be increased only to a maximum of -48°C.
Otherwise, the cooling effect will be impaired.
♦ The coolant concentration must not be reduced by adding
water even in warmer seasons and in warmer countries.
Frost protection must be guaranteed down to at least -25°C.
♦ The temperature reading on the refractometer corresponds
to the »ice flocculation point«. Flakes of ice may start form‐
ing in the coolant below this temperature.
♦ Never reuse old coolant.
♦ Use only a water/coolant additive mixture as a slip agent for
coolant hoses.
4.30.1
Coolant level: checking, replenishing
coolant if necessary
NOTICE
If the coolant expansion tank is sealed with a lead seal -1-,
seal it again after checking or replenishing the coolant level.
– Check coolant level in coolant expansion tank with engine
cold.
1 - Pre-delivery inspection
Coolant level on seam -3- of coolant expansion tank or above:
– No activity required, coolant level OK.
Coolant level between seam -3- and “min. mark” -4- on coolant
expansion tank:
– Replenish coolant up to “max. mark” -2-.
– Fit a new lead seal to coolant expansion tank.
Coolant level below “min. mark” -4-.
– Check cooling system for leaks ⇒ 4-cyl. injection engine (hy‐
brid); Rep. gr. 19; Cooling system/coolant.
– Replenish coolant up to “max. mark” -2-.
– Fit a new lead seal -1- to coolant expansion tank.
2 - 1st oil change service at 15,000 km or after 1 year
Coolant level at “MAX. marking” -2-:
– No action necessary.
Coolant level between “MIN. marking” -4- and “MAX. marking”
-2-:
4. Descriptions of work
95
Passat 2015 ➤, Passat 2019 ➤, Passat Variant 2015 ➤, Passat Variant 2019 ➤
Maintenance - Edition 11.2020
– Replenish coolant up to “max. mark” -2-.
– Fit a new lead seal to coolant expansion tank.
Coolant level below “min. mark” -4-.
– Check cooling system for leaks ⇒ 4-cyl. injection engine (hy‐
brid); Rep. gr. 19; Cooling system/coolant.
– Replenish coolant up to “max. mark” -2-.
– Fit a new lead seal -1- to coolant expansion tank.
4.30.2
Frost protection: checking, replenishing
coolant additive if necessary
Special tools and workshop equipment required
♦ Refractometer -T10007A-
♦ Refractometer -T10007B-
Note
Read precise value for the following tests at light-dark border.
Using a pipette, place a drop of water on the glass to improve
the readability of the light-dark border. The light-dark border can
be clearly recognised on the “WATERLINE”.
– Check concentration of coolant additive using refractometer
(refer to operating instructions).
Scale -1- of the refractometer is calibrated for the coolant addi‐
tives G12++ and G12evo.
Scale -2- of the refractometer is calibrated for the coolant addi‐
tive G13.
– If frost protection is insufficient, drain some coolant and top
up with coolant additive ⇒ page 95 .
96
4. Descriptions of work
Passat 2015 ➤, Passat 2019 ➤, Passat Variant 2015 ➤, Passat Variant 2019 ➤
Maintenance - Edition 11.2020
Note
♦ 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.
4.30.3
Mixing ratio
NOTICE
Only distilled water may be used for mixing coolant additives.
The use of distilled water ensures optimum protection against
corrosion.
Anti-freeze protection to
Coolant additive
portion
Distilled water
-25°C
-36°C
approx. 40%
approx. 50%
approx. 60%
approx. 50%
4.31
Diesel fuel filter: renewing
CAUTION
Risk of burns from very hot fuel.
♦ In extreme cases the fuel lines and the fuel can reach a
temperature of 100°C. Allow the fuel to cool down before
disconnecting the lines - risk of scalding.
♦ Wear protective gloves.
♦ Wear safety goggles.
Risk of injury due to highly-pressurised fuel.
♦ To release pressure in fuel system, place clean cloth
around connection and carefully undo connection.
Special tools and workshop equipment required
♦ Safety gloves
♦ Safety goggles
Note
Observe relevant disposal regulations.
Removing
NOTICE
♦ Ensure that no diesel fuel contacts other components in
the engine compartment. Clean immediately, if necessary.
– Switch off ignition.
4. Descriptions of work
97
2024 VW Passat Owner's Manual
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