Opel 1900 1973 Service Manual page 520

air is attained, as the water does not cool down in the
second part of the core.
A Water Outlet
B Water Inlet
The center lever actuates the two-stage blower mo-
tor.
Lever positions:
Left to Center - Motor Switched Off
Right of Center - Lo Blower
Right - Hi Blower
The lower lever opens and closes the air door which
channels the air flow to either the lower heater out-
lets or to the defroster outlets.
In the left lever position, the air inlet is closed. Up
to the center position, the air is directed t,o the lower
heater outlets.
When moving the lever from center position towards
the right, the air flow to the lower heatezr outlets is
reduced and increased to the defroster csutlets.
With the lever in its right position, the air is directed
to the defroster outlets only. For windshield defrost-
ing, all levers have to be moved to the right.
FUNCTION OF THE HEATER AND VENTILATION
SYSTEM
The engine hood is provided with slots in front of the
windshield. The air is directed through the slots into
the heater housing located in the engine compart-
ment, flows into the air distributor housing, and
from there to the lower heater outlets and,/or defros-
ter outlets, depending on the position of the control.
The two-stage blower motor is arranged in the heater
housing above the heater core and actuated by the
center control. The blower motor draws in the air
entering through the slots, blows the air through the
heater core into the air distributor housin:?, and from
there to the lower heater outlets and/or defroster
outlets, depending on the position of the lower con-
trol. See Figure 9A-32.
The heater valve regulates the flow of coolant
through the heater core, thereby varying t:he temper-
ature of the air flow past the core.
The ventilation of vehicle interior is completed by a
draft-free air circulation pattern. Vent slots are ar-
ranged below the back window which are: connected
through channels to the rear quarter iside panel.
From here, the inside air escapes into the! open. The
HEATER SYSTEM. OPEL 1900. MANTA
Figure 9A-32 Air Flow
head wind (caused by the car traveling down the
road) promotes this process so that there is always
fresh air in vehicle interior.
On the Model 54 Station Wagon, there will be no air
outlets in the rear. For adequate flow-through type
ventilation, it will be necessary to open a rear win-
dow.
Aside from the fresh air admission through the
heater system, two fresh air inlet nozzles are ar-
ranged in the center of the instrument panel. These
nozzles can be turned to direct the air flow in the
desired direction. In addition, rotary flaps allow the
regulation of the entering air or to shut off the air
completely.
These nozzles admit unheated fresh air only and
operate independent of the heater and defroster sys-
tem.
DIAGNOSIS
HEATER SYSTEM TROUBLE DIAGNOSIS
TROUBLE
Temperature of heated air at outlets too low.
CAUSE AND CORRECTION
Check radiator cap for proper sealing action. Re-
place, if necessary.
Check for adequate coolant supply. If level is down,
correct cause of coolant loss and refill radiator.
Inspect hose for kinks. Relieve kink or replace hoses.
Check thermostat operation by measuring tempera-
ture of coolant at radiator. Temperature should be
within 5 d e g r e e s F. of thermostat rated value (189
degrees F.).