MG MGA Twin Cam Workshop Manual page 254

Secure the pipe by tightening the union firmly. Fit the two clips (18) to the oil filter pipe and fasten them
to the clips on the copper return pipe using two screws (21), two washers (26), and two nuts (24).
Connect the heater outlet to the copper return pipe with the short rubber water hose (12) and secure
at both ends with two clips (32).
Fit the two demist tubes (14) to the holes in the lower heater case seen under the fascia above the air
outlet door using six screws (20). Fit the 14 in. (35-6 cm.) air hose (6) to the left-hand demist tube and
the 25 in. (63-5 cm.) air hose (7) to the right-hand demist tube. Connect both air hoses to the demist
nozzles already fitted under the dash panel with the two rubber adaptors (19).
Connect the switch leads from the temperature control lever to the green lead and the green lead with
brown tracer issuing from the harness below the fascia (on the car these two wires may be found
already joined together by a snap connector). Connect the leads from the heater motor to the black
lead and the green lead with brown tracer issuing from the harness behind the heater (snap
connectors on all leads). Reconnect the battery leads.
Refill the cooling system, start the engine and check for water leaks. Push the 'AIR' and 'DEMIST'
knobs in, pull the central control out and slide the temperature control lever to the "MAX'. position. If
the heater has been fitted correctly a cool stream of air will enter the car interior through the air outlet
door and will be heated as the cooling system warms up.
If the water return hose does not warm up in a few minutes an air-lock may be present in the system. If
this happens switch off the engine and remove the rubber hose from the copper return pipe. Extend
the rubber hose by some temporary means so that the water will flow back into the radiator through
the filler neck. Plug the copper pipe temporarily.
Start the engine and allow it to run at a fast idling speed. Note the water flow-back into the radiator.
When this is smooth and bubble-free reconnect the hose to the copper pipe and tighten the clip as
quickly as possible.
Fit the longer air hose (9) between the rear of the air hose connector on the left-hand side of the
radiator and the air intake on the heater. Secure at both ends using the two flexible clips (31) and
fasten the hose to the bonnet drain channel with two cleats (17) together with two screws (23), two
washers (27), and two nuts (25). It may be necessary to drill two #in, (5-16 mm.) diameter holes in the
bonnet drain channel for the securing screws.
When draining the cooling system, it is not possible to completely drain the heater unit. Anti-freeze
must, therefore, be used in the cooling system when frost is anticipated.
MGA' (TWIN CAM) HEATER KIT. Part No. 8G9037
Item number
1
2
3
4
5
6
7
8
9
Description
Heater assembly
Lever control assembly
Push-pull control Air
Push-pull control 'Demist
Cable
Air hose (1 ½ in. X 14 in.)
Air hose (1 ½ in. X25 in.)
Air hose short
Air hose-long (4 in. x 36 in.)
254
Part Number Quantity
AHH5760 1
AHH5531 1
AHH5786 1
AHH5787 1
AHH5529 1
AHH5427 1
AHH5428 1
AHH5394 1
AHH5785 1
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