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Why must i discharge the air conditioning refridgerant prior to removal of the heater core on a 2003 c230 mercedes 1.8l coupe.
There is only heater pipes connected to the heater core, one in one out. So,why must i discharge the air conditioning refrigerant prior to removing and replacing the core as per HAYNES repair manual.
The reason in why you must evacuate the a/c system with an a/c machine before you can remove the heater core is because the evaporator is located inside of the heater core box assembly. So before the heater core box assembly can be removed the a/c system must be evacuated then you can disconnect the a/c lines that go through the firewall to the evaporator.
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In order to remove most heater cores involves discharging the air conditioning system, draining the radiator fluid , disconnect blower motor, disconnect the air-conditioning lines, special tools are needed for most models. Remove PCM ( COMPUTER ) LABEL AND DISCONNECT electrical connectors, disconnect vacuum hoses. Hope this helps, but really should be done by qualified mechanic.
Fig. 1: When installing the new heater core take great care not to bend or damage the fins or tubing
[IMG]http://i665.photobucket.com/albums/vv17/technovative/Isuzu-Pickup-Heater-Core.gif[/IMG] Click here if image doesn't display.
Disconnect the negative battery cable.
Drain the engine coolant into a suitable container.
CAUTION When draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.
Disconnect the heater hoses. Be careful not to damage the core by pulling on the hose to remove. Cut the hoses if they will not come off easily.
Remove the instrument panel.
Disconnect the resistor assembly.
If possible, disconnect and move the duct (non air conditioning) or the evaporator housing (air conditioning) to the right to gain clearance for the heater unit. If equipped with air conditioning, do not disconnect air conditioning system until absolutely necessary. Refer to Section 1 for discharging, evacuating and recharging the system.
Remove the instrument panel stay and heater unit.
Disassemble the heater unit by removing the duct, mode control case, core assembly and heater core.
To install:
Assemble the heater unit by installing the duct, mode control case, core assembly and heater core.
Install the heater unit and instrument panel stay.
Connect the duct (non air conditioning) or the evaporator housing (air conditioning) to the heater unit. Evacuate and recharge the air conditioning system if the system was discharged to remove the evaporator assembly.
Connect the resistor assembly.
Install the instrument panel as outlined in this section.
Connect the heater hoses. Be careful not to damage the core by pulling on the hose.
Refill the engine coolant into a suitable container.
Connect the negative battery cable and check for leaks.
Disconnect and remove the negative battery.
CAUTION
After disconnecting the negative battery cable, wait 2 minutes for
the driver-s/passenger-s air bag system capacitor to discharge before
attempting to do any work around the steering column or instrument.
Drain the cooling system into a clean container for reuse.
Remove the instrument panel by performing the following procedure:
Turn the steering wheel in the straight-ahead position.
Remove the knee blocker from the instrument panel.
Remove the steering column; do not remove the air bag module, the
steering wheel or switches from the steering column.
From under the driver-s side of the instrument panel, disconnect
the following items:
Instrument panel wiring harness connector from the 100-way wiring
harness connector at the left side of the inner panel.Side window demister hose at the heater/air conditioning housing
demister/defroster duct on the driver-s side.
Remove the glove box.
Reaching through the glove box opening, disconnect the following
items:
Two halves of the heater/air conditioning system vacuum harness
connector.Instrument panel wiring harness connector from the heater/air
conditioning system wiring harness connector.Instrument panel wiring harness connector from the passenger-s
side air bag module wiring harness connector.Side window demister hose at the heater/air conditioning housing
demister/defroster duct (passenger-s side).Two halves of the radio antenna coaxial cable connector.Two instrument panel wiring harness connectors from the passenger
air bag ON/OFF switch wiring harness connector.Passenger-s side air bag ON/OFF switch wiring harness from the
retainer clip on the plenum bracket that supports the heater/air
conditioning housing just inboard of the fuse block module.Two lower passenger-s side air bag module bracket-to-dash panel
nuts.
Remove the upper cover from the instrument panel.
Remove the 3 instrument panel-to-door hinge pillar screws.
Remove the 4 upper instrument panel-to-dash nuts.
Using an assistant, remove the instrument panel from the vehicle.
If equipped with air conditioning, discharge and recover the air
conditioning system refrigerant.
Disconnect the refrigerant lines from the evaporator. Plug the
refrigerant openings to prevent evaporation.
Disconnect the heater hoses from the heater core tubes.
Disconnect the heater/air conditioning system vacuum supply line
connector from the T-fitting near the heater core tubes.
In the engine compartment, remove the 5 heater/air conditioning
housing-to-chassis nuts. If necessary, loosen the battery hold-downs and
reposition the battery for access.
Remove the cowl plenum drain tube from the heater/air conditioning
housing stud; it-s located behind the cylinder head on the cowl.
From the bottom of the heater/air conditioning housing, remove the
floor duct.
On the passenger side, remove the heater/air conditioning
housing-to-plenum bracket screw.
Pull the heater/air conditioning housing down far enough to clear
the defrost/demist and fresh air ducts, then, rearward far enough to
clear the mounting studs and the evaporator drain tube to clear the dash
panel holes.
Remove the heater/air conditioning housing assembly from the
vehicle.
Remove the heater/air conditioning housing upper case.
Lift the heater core from the lower half of the heater/air
conditioning housing.
To install:
Assemble the heater core into the lower half of the heater/air
conditioning housing.
Install the heater/air conditioning housing upper case.
Install the heater/air conditioning housing assembly to the
vehicle.
On the passenger-s side, install the heater/air conditioning
housing-to-plenum bracket screw.
At the bottom of the heater/air conditioning housing, install the
floor duct.
Install the cowl plenum drain tube to the heater/air conditioning
housing stud; it-s located behind the cylinder head on the cowl.
In the engine compartment, install the 5 heater/air conditioning
housing-to-chassis nuts.
Connect the heater/air conditioning system vacuum supply line
connector to the T-fitting near the heater core tubes.
Connect the heater hoses to the heater core tubes.
Connect the refrigerant lines to the evaporator.
If equipped with air conditioning, evacuate and charge the air
conditioning system refrigerant.
Install the instrument panel by performing the following
procedure:
Using an assistant, install the instrument panel to the vehicle.
Install the 4 upper instrument panel-to-dash nuts.
Install the 3 instrument panel-to-door hinge pillar screws.
Install the upper cover to the instrument panel.
Reaching through the glove box opening, connect the following
items.
Two lower passenger-s side air bag module bracket-to-dash panel
nuts.Passenger-s side air bag ON/OFF switch wiring harness to the
retainer clip on the plenum bracket that supports the heater/air
conditioning housing just inboard of the fuse block module.Two instrument panel wiring harness connectors to the passenger
air bag ON/OFF switch wiring harness connector.Two halves of the radio antenna coaxial cable connector.Side window demister hose at the heater/air conditioning housing
demister/defroster duct (passenger-s side).Instrument panel wiring harness connector to the passenger-s side
air bag module wiring harness connector.Instrument panel wiring harness connector to the heater/air
conditioning system wiring harness connector.Two halves of the heater/air conditioning system vacuum harness
connector.
Install the glove box.
Under the driver-s side of the instrument panel, connect the
following items:
Side window demister hose at the heater/air conditioning housing
demister/defroster duct on the driver-s side.Instrument panel wiring harness connector to the 100-way wiring
harness connector at the left side of the inner panel.
Install the steering column.
Install the knee blocker to the instrument panel.
Connect and remove the negative battery.
Refill the cooling system.
Run the engine to normal operating temperatures; then, check the
climate control operation and check for leaks.
HATE TO SAY HEATER CORE IS A GARAGE OR DEALERSHIP FIX.THE DEALERSHIP HAS TO DISCHARGE AIR CONDITIONER SYSTEM.THE CRASH PAD AND INSTRUMENT PANEL HAS TO BE REMOVED .YOU CAN BUY A HAYNES REPAIR MANUAL IT WILL SHOW YOU BUT THE DEALERSHIP HAS TO DISCHARGE THE AIR CONDITIONER SYSTEM FIRST.FOR SAFETY DUE TO AIR BAGS AND TURN OFF RADIO.DISCONNECT REMOVE BATTERY NEGATIVE CABLE FOR 20 MINUTES TO DISARM AIRBAGS IN STEERING WHEEL AND INSTRUMENT CLUSTER.WHEN YOU FINISH THE REPAIR.WHEN PUTTING NEGATIVE BATTERY BACK ON BATTERY.WITH THE IGNITION SWITCH ON POSITION ENGINE OFF THE AIR BAG LIGHT SHOULD ILLUMINATE FOR 4 TO 8 SECONDS THEN GO OFF.
Drain the engine coolant into a suitable container.
CAUTION
When draining engine coolant, keep in mind that cats and dogs are
attracted to ethylene glycol antifreeze and could drink any that is
left in an uncovered container or in puddles on the ground. This will
prove fatal in sufficient quantity. Always drain coolant into a
sealable container. Coolant should be reused unless it is contaminated
or is several years old.
Disconnect the heater hoses. Be careful not to damage the core by
pulling on the hose to remove. Cut the hoses if they will not come off
easily.
Remove the instrument panel.
Disconnect the resistor assembly.
If possible, disconnect and move the duct (non air conditioning)
or the evaporator housing (air conditioning) to the right to gain
clearance for the heater unit. If equipped with air conditioning, do
not disconnect air conditioning system until absolutely necessary.
Refer to
for discharging, evacuating and recharging the system.
Remove the instrument panel stay and heater unit.
Disassemble the heater unit by removing the duct, mode control case, core assembly and heater core.
To install:
Assemble the heater unit by installing the duct, mode control case, core assembly and heater core.
Install the heater unit and instrument panel stay.
Connect the duct (non air conditioning) or the evaporator housing
(air conditioning) to the heater unit. Evacuate and recharge the air
conditioning system if the system was discharged to remove the
evaporator assembly.
Connect the resistor assembly.
Install the instrument panel as outlined in this section.
Connect the heater hoses. Be careful not to damage the core by pulling on the hose.
Refill the engine coolant into a suitable container.
Connect the negative (-) battery cable and check for leaks.
Gp to any auto parts store and ask the clerk to show you where the air filter is located. Ask about the new permanent air filter which costs a little more, maybe twice as much but never needs to be replaced again.
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