Heater Core Removing and Installing
Heater Core Removing and Installing
• Due to space limitation when the instrument panel is installed, it is not possible to install the factory-installed heater core and clamps - B - and - C - again. If a factory installed heater core (Original part) must be installed again, remove the instrument panel and the air guide leading to the "Defrost" vent. Coat the O-rings with coolant (as described for installing a replacement heater core) on the coolant pipes - D - and - E - and then push the coolant pipes - D - and - E - (with the O-ring) from the top into the connections in the heater core - A -. Hold the coolant pipes - D - and - E - in the heater core and install the clamps - B - and - C -. Further assembly is performed as described for installing a replacement part - heater core.
Removing
- Perform the preparation work for removing the heater core. Refer to => [ Heater Core Preparing for Removal ] Heater Core Preparing For Removal.
- Release pressure in cooling circuit by opening cap on coolant expansion tank.
- Mark the arrangement of coolant hoses - A - (supply to cylinder head) and - B - (return to coolant pump).
• The heater core is designed for a specific coolant flow direction. Therefore, coolant hoses must be connected on the correct sides.
• Bleed the coolant circuit.
- Clamp the coolant hoses - A - and - B - with hose clamps.
- Cover the area beneath connections for coolant hoses - A - and - B - for example with absorbent paper.
- Remove coolant hoses - A - and - B - from connections to heater core.
- Insert one section each of hose - A - and - B - on to both connections to heater core.
- Place a container - B - under the other end of the hose - C -.
- Using a compressed air gun - D -, carefully blow coolant out of heater core (into container - B -) via hose - A -.
- Remove the clamps - B - and - C - from the heater core connectors - A -.
- Loosen both coolant pipes - D - and - E - from the heater core connectors - A -.
- Remove the heater core - A - in the direction of the arrow - arrow -.
• The upper illustration shows a heater core with connectors as it is installed in production. If the heater core was already exchanged once, then both coolant pipes are held in the replacement heater core with a bracket - A -. Remove the screw - B - in this heater core. Install a longer screw - C - (with a M5 thread) all the way to the end as shown in the illustration and with this screw, loosen the bracket - A - from the connection.
Installing
Installation is carried out in the reverse order while noting the following:
- Depending on the A/C version , cover the heater core with the foam seal provided - A - through - D -.
1 Heater core for a vehicle equipped with a "Basis" A/C system with left- or right-hand drive.
2 Heater core for a vehicle equipped with a "Comfort" A/C system.
3
- Check the seals on the heater core; only install a heater core with seals that are not damaged and are secured glued on.
• If the vehicle has the "Comfort" A/C system, then there are different temperature settings for the right and left sides as well as for the rear. The seals - C - and - D - separate the air guides in the air conditioner from each other. Refer to => [ Air Routing in Air Intake Housing and A/C Unit ] Air Routing In Air Intake Housing and A/C Unit.
• The heater core has a color mark that shows where to affix the seal - C -. The seal - D - must be applied to the center of the heater core as illustrated.
• The seal - C - may have different lengths (a short version as illustrated or a long version which reaches all the way around the heater core). If the heater core is delivered with the longer seal - C -, then attach it all the way around the heater core.
• Seal may curl up on insertion if not correctly bonded on.
• If the seal is damaged or installed incorrectly, cold air can flow over the heater core; on vehicles equipped with the "Comfort" A/C system, it is possible that there is no clear separation between the various areas.
- Check the A/C unit and the evaporator - F - with the heater core removed - A - (via heater core opening) for dirt.
- Remove any dirt or coolant which has leaked out of the A/C unit (for example, after removing a leaking heater core).
- Check both connections - A - and - B - on the heater core - C - for damage and dirt.
- Grease both connections - A - and - B - on the heater core - C - with silicone grease.
• The silicone grease part number is G 000 405 A2. Refer to Electronic Parts Catalog (ETKA).
- Lightly moisten the seals - D - (contained in the heater core delivery) with coolant (or lightly with silicone grease).
- Install the new seals - D - on both heater core coolant pipes - E - and - F -.
- Push the heater core - A - into the A/C unit.
- Support the heater core - A -, for example, with a plastic wedge - B - on the center tunnel - C - so that it cannot slip down when attaching the coolant pipes.
- Install a longer screw - G - (with a M5 thread) all the way to the stop in the bracket - C - as shown in the illustration.
- Install and push both coolant pipes - E - and - F - with each seal - D - into the heater core connector flange all the way.- H -.
Risk of leaks from the heater core.
• Squeezed O-ring seals, sharp-edged or coolant pipes/clamps that have not been inserted completely may lead to leaks.
• Do not bend the coolant pipes - D - and - E - when pushing them into the connections on the heater core.
- Make sure the seals - C - between the coolant pipes - D - and - E - and the flange connection - B - on the heater core - A - fit securely.
Seals that are incorrectly installed or jammed - C - will leak.
• The seals - C - must be installed completely into both the coolant pipe connections - D - and - E - and the flange connections - B -.
- Secure both coolant pipes - E - and - F - with the bracket - C - on the heater core flange - H -.
• The screw - G - is used to help with the installation and must be removed after the bracket is installed.
- Insert the screw - A - and the washer - B - and tighten the screw - A -.
Screw tightening specification - A - 2.5 Nm.
- Remove the screw - G -.
- Make sure the grommet - H - fits correctly in the back of the plenum chamber.
- Properly connect the coolant hoses to the heater core, pay attention to the marking.
A Supply hose from cylinder head
B Return to the coolant pump
- Connect the coolant hose - A - to the heater core coolant pipe (pay attention to the marking) and secure it with the clamp - D -.
- Attach the coolant hose for the heater core - B - onto the coolant pipe - F - just far enough as to not cover the bleed hole - G -.
- Remove the hose clamp from the coolant hose - A -.
- Fill the coolant expansion tank with coolant.
- Carefully force the coolant out of the coolant overflow reservoir into the heater core using, for example, the hand pump from the Cooling System Tester (V.A.G 1274/).
- As soon as the coolant comes out the ventilation hole - G -, install the coolant hose - B - on to the coolant pipe - F - at the marking.
- Secure the coolant hose - B - with the clamp - E - on the marked location.
- Remove the hose clamp from the coolant hose - D -.
- If necessary, add more coolant to the coolant expansion tank.
• This procedure completely bleeds the cooling system. If, for some other reason, there is still some air in the cooling system, install all removed components and bleed the system once again.
Check the connections at the heater core for leaks as follows:
- Carefully increase the pressure in the coolant circuit by using, for example, the hand pump of the cooling system tester (V.A.G 1274/).
- Check coolant circuit for leaks, pay particular attention to the connection between coolant hoses and heater core.
• When bleeding coolant circuit, take special care to ensure complete bleeding of heater cores. If there are still air bubbles in the heater core, it may cause the customer to complain of insufficient heating performance in winter or different air temperature from vents at same setting in regulated mode. Refer to => [ Heat Output and Temperature Door Activation, Checking ] Heat Output and Temperature Door Activation, Checking.
• Depending on vehicle equipment and on engine, heat insulation has been applied to coolant hoses, these must not be damaged and must be re-applied after installing.
- Install all the components in reverse sequence, refer to => [ Heater Core Preparing for Removal ] Heater Core Preparing For Removal.
With high voltage systems (hybrid vehicles)
- Install the cowl panel - C -.
- Make sure the electric drive power and control electronics (JX1) - D - and wires - D - are installed correctly.
- Energize the voltage to the high voltage system.
Restart the high voltage system
Risk of electrocution
Death or serious bodily injury by electric shock
• People with electric/medical life- and health sustaining devices in or on their person must not perform any work on the high voltage system for safety reasons. Internal pain killer pumps, implanted defibrillators, pacemakers, insulin pumps and hearing aids among others are considered life- and health sustaining devices.
• The high voltage system may only be restarted by qualified personal (Audi high voltage technicians).
• Assure that the restart is performed exclusively using the Vehicle Diagnosis Tester according to the "Guided Fault Finding".
• The qualified personal (Audi high voltage technician) restarts the vehicle.
• The qualified personal (Audi high voltage technicians) marks the vehicle by attaching warning labels.
• Restart the high voltage system:
• Connect the vehicle diagnosis tester
• Select the Guided Fault Finding mode
• Using the GO TO button, select the following menu commands
• Functions/Component selection
• Body
• Electrical Equipment
• OBD-capable system
• 8C - Hybrid battery management -J840
• 8C - Hybrid battery management, functions
• 51 - High voltage restart (Rep.Gr. 93)
For vehicles without a high voltage system
- Reconnect the battery ground connection; when doing this, pay attention to the notes regarding reconnecting the battery.
All vehicles
- Switch on the ignition.
- Perform a basic setting and the output Diagnostic Test Mode (DTM) on the A/C system using the Vehicle diagnostic tester in "Guided Fault Finding".
• On this vehicle, the control motors are equipped with electronics. During the first basic setting, a new control motor learns its position on the air conditioner and can then be controlled by the Climatronic Control Module (J255) (currently all control motors are identical). Refer to the Vehicle diagnostic tester in "Guided Fault Finding".
• During the basic setting, the control motors are assigned and adapted corresponding to the switching sequence of the wiring. If this sequence does not conform the specification, the control motors will adapt incorrectly and the door control will be wrong. Refer to => [ A/C Control Motor Block Diagram ] A/C Control Motor Block Diagram (A/C control motors block diagram).
- Switch on the ignition.
- Check the Climatronic Control Module DTC memory and erase any displayed malfunction if necessary using the Vehicle diagnostic tester in "Guided Fault Finding".
- Adjust and check the air flow direction on the different air ducts via Climatronic control module, if the quantity of air actually changes at each setting.