Audi Workshop Service and Repair Manuals

Removing and installing heat exchanger Special tools and workshop equipment required t  Hose clamps up to 25 mm -3094- t  Engine sealing plug set -VAS 6122- t  Drip tray for workshop crane -VAS 6208- t  Hose clip pliers -VAS 6362-

Removing –  Place the drip tray for workshop crane -VAS 6208- under the engine. –  Mark the arrangement of the coolant hoses. –  Vehicles with petrol engine: Pinch off the coolant hoses -1- and -4- with hose clamps -3094- and detach from the heat exchanger by unfastening the hose clips -2, 3-.

–  Vehicles with TDI engine: Remove the air cleaner housing → Rep. gr.23. –  Pinch off the coolant hoses -1- and -4- with hose clamps -3094- and detach from the heat exchanger by lifting the retaining clips -2, 3-.

–  Fit a short hose -2- on one connection. l  Insert the compressed air gun -3- in the end of the hose. –  Hold a vessel -4- under the second connection -1- and use the compressed air gun to carefully blow the coolant out of the heat exchanger.

–  Screw out the bolt -2-. –  Detach the adapter -1- from the connections of the heat exchanger. –  Seal open lines and connections with clean plugs from the Engine sealing plug set -VAS 6122-.

–  Move the front seats to the rearmost position. –  Remove the centre console → Rep. gr.68. –  Detach the insulation -1- if fitted.

–  Detach the connecting collar -1- to the rear footwell vent.

–  Vehicles with supplementary air heater element -Z35-: Unplug the connector -1- and remove from the holder. To do so, press aside the retainer -3- and pull the connector -2- in -arrow direction- out of the holder.

–  Unscrew the nut -1- and lay bare the earth wire -2-.

–  Protect the floor covering in the area beneath the heat exchanger with impermeable sheeting and absorbent paper. –  If applicable, detach the cover panel -2- from the velcro strip. –  Prise off -arrow- the retaining clips -1- all round.

–  Release the bottom section -1- at the air distribution housing -2- downwards and take out to the right -arrow-. –  Take the heat exchanger -3- out of the bottom section. Installing Install in reverse order, paying attention to the following: l  Tightening torque (bolt at adapter for coolant hoses 8 Nm) → Chapter and → Chapter. l  Tightening torque (bolt at earth connection to supplementary air heater element -Z35- 9 Nm → Current flow diagrams, Electrical fault finding and Fitting locations (fitting locations).   Note Replace the O-rings .

Vehicles with heater: –  Make sure the grommet -1- is correctly positioned in the bulkhead -2-.

Vehicles with air conditioner: –  Make sure the grommet -1- is correctly positioned in the bulkhead -2-. All vehicles (continued): –  Check the heater slot for contamination with the heat exchanger removed. –  Remove any dirt or residual coolant. –  Vehicles with TDI engine: Check the supplementary air heater element -Z35- for contamination and clean if necessary → Chapter.

–  Check the foam seals -1, 3- attached to the heat exchanger -2- for damage and replace if necessary.   Note t  The foam seal may curl up on insertion if not correctly bonded on. t  Cold air may flow past the heat exchanger if the foam seal is damaged or not properly fitted. –  Insert the heat exchanger in the bottom section. –  Position the bottom section at the heater and secure with the retaining clips.

–  Make sure the grommet -2- is positioned in the groove -1- at the heat exchanger -3-. –  Press on the adapter -5- with new O-rings at the heat exchanger connections. –  Tighten the bolt -4-.   Note t  Make sure the grommet and heat exchanger at the bulkhead penetration are correctly positioned. t  Water will ingress into the passenger compartment if the grommet is damaged or not correctly fitted. –  Fill up with coolant and bleed in the specifed manner → Rep. gr.19.   Note t  When bleeding the coolant circuit, take special care to ensure complete bleeding of the heat exchanger. If air bubbles remain in the heat exchanger, complaints may be received about a lack of heat output in winter or differences in the temperature of the air flowing out of the vents with the same setting in control mode. Checking heat output: Heater → Chapter, manually controlled air conditioner → Chapter, automatically controlled air conditioner → Chapter. t  Depending on the vehicle equipment and engine, there is heat insulation on the coolant hoses; the insulation must not be damaged and must be re-attached after installation. –  Install the centre console → Rep. gr.68. –  Check operation of the heater, air conditioner.