Heater Core, Removing And Installing: Removing

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-- Perform The Preparation Work For Removing The Heater Core. Refer To HEATER CORE, PREPARING FOR REMOVAL .

-- Open The Cap On The Coolant Expansion Tank And Release The Pressure In The Coolant System. Refer To COOLANT, DRAINING AND FILLING [CAUA] , COOLANT, DRAINING AND FILLING [CFSA] , COOLANT, DRAINING AND FILLING [CAEB, CPMA, CAED, CPMB] , COOLANT, DRAINING AND FILLING [CALA] and COOLANT, DRAINING AND FILLING [CAED, CAEB, CPMB, CPMA] .

-- Mark the arrangement of coolant hoses -A- (supply to cylinder head) and -B- (return to coolant pump).

Fig 1: Identifying Battery (+) Cable, Coolant Hoses And Plenum Chamber Grommet

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NOTE:

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. Refer To COOLANT, DRAINING AND FILLING [CAUA] , COOLANT, DRAINING AND FILLING [CFSA] , COOLANT, DRAINING AND FILLING [CAEB, CPMA, CAED, CPMB] , COOLANT, DRAINING AND FILLING [CALA] and COOLANT, DRAINING AND FILLING [CAED, CAEB, CPMB, CPMA] .

-- 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 The Coolant Hoses - A And B- From The Connections To The A/C Heater Core. Refer To COOLANT PIPES [CAUA] , COOLANT PIPES [CFSA] , COOLANT PIPES [CAED, CAEB, CPMB, CPMA] , COOLANT PIPES [CALA] .

-- Insert one section each of hose -A and B- on to both connections to heater core.

Fig 2: Using A Compressed Air Gun Carefully Blow Coolant Out Of Heater Core

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-- 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 connections -A-.

Fig 3: Check A/C Unit And Evaporator With Heat Exchanger Removed

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-- Loosen both coolant pipes -D and E- from the heater core connections -A-.

-- Remove the heater core -A- in the direction of the -arrow-.

NOTE:

The upper illustration shows a heater core with connectors as it is installed in production. If the heater core was already replaced once, then both coolant pipes are held in the replacement heater core with a bracket -A-. Remove the bolt -B- on 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.

Fig 4: Checking Coolant Circuit For Leaks, Pay Particular Attention To Connection Between Coolant Hoses And Heater Core Engine Mechanical

Courtesy of AUDI OF AMERICA, LLC