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Operation of heater coolant shut-off valve N279 > < Incorporation of auxiliary heater

A5

Removing and installing circulation pumpV55
Removing and installing circulation pump -V55-
  WARNING
The cooling system is pressurised. When the engine is warm, the coolant temperature may be in excess of 90 °C. Dissipate pressure and allow to cool down before performing repairs. Dissipate the pressure in the coolant circuit by opening the cap at the coolant expansion tank → Engine, mechanics; Rep. Gr.19.
  Note
t  Depending on vehicle equipment, the circulation pump -V55- may also be actuated by the supplementary heater control unit -J364- when a request is transmitted by the corresponding engine control unit or the operating and display unit, Climatronic control unit -J255- by way of the data bus → Vehicle diagnostic, testing and information systemVAS 5051/, “Guided fault-finding function” and → Current flow diagrams, Electrical fault finding and Fitting locations.
t  As of Model Year 2010 a start/stop system will be available as an optional extra for this vehicle in conjunction with certain engines. On these vehicles, pay attention to the correct version of the air conditioner operating and display unit, Climatronic control unit -J255- and of the auxiliary heater → Electronic parts catalogue and → "Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051.
t  On vehicles with a start/stop system the circulation pump -V55- of the auxiliary heater is actuated during the stop function by the supplementary heater control unit -J364-. Via the data bus, -J364- is requested by the air conditioner operating and display unit, Climatronic control unit -J255- to switch on -V55- → "Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051
t  The circulation pump -V55- is incorporated into the auxiliary heater tubing system.
t  When removing the circulation pump -V55-, only pinch off, unfasten and disconnect the coolant hoses at the circulation pump -V55- to avoid having to bleed the entire engine coolant circuit.
Special tools, testers and other items required
   
t  Hose clamps up to Ø 25 mm -3094-
  W00-0079
t  Hose clip pliers -VAS 6340- (or pliers for spring strap clips -VAS 5024/-)
Removing
–  Switch off ignition (and auxiliary heater).
–  Dissipate the pressure in the coolant circuit by opening the cap at the coolant expansion tank → Engine, mechanics; Rep. Gr.19.
–  Remove the front right wheel → Running gear; Rep. Gr.44.
–  Remove the front right wheel housing liner → General body repairs, exterior; Rep. Gr.63.
  Note
The following illustration shows the position of the circulation pump -V55- on an Audi A5 Coupé. The position of the circulation pump -V55- differs slightly on the Audi A4 and Audi Q5. On these other vehicles the work is however to be performed in the same manner as described for the Audi A5 Coupé.
  W00-1179
–  Pinch off the coolant hoses -6- and -8- (e.g. with hose clamps up to Ø 25 mm -3094-).
–  Unfasten the clamps -5-.
–  Detach the coolant hose -6- from the circulation pump -V55--2-.
–  Slacken off the bolt -3- and detach the clip -7-.
–  Disconnect the circulation pump -V55--2- from the coolant hose -4-.
–  Unplug the connector -1- from the circulation pump -V55- and take out the circulation pump.
Installing
Install in reverse order; paying attention to the following:
  Note
t  If the coolant circuit has been drained, a new circulation pump -V55- is not to be started up until the coolant circuit has been filled, as dry running could destroy the new pump.
t  As only a small quantity of coolant escapes from the coolant circuit on removing the circulation pump -V55- as described above, coolant runs into the circulation pump -V55- following installation and after removing the hose clamps (additionally open the expansion tank cap) and there is no danger of dry running.
–  Do not plug in the connector to the circulation pump -V55- until the hose clamps have been removed (and the coolant circuit has been filled).
–  Bleed the coolant circuit → Chapter.
Tightening torques → Chapter
  A82-10112

Operation of heater coolant shut-off valve N279 > < Incorporation of auxiliary heater