The MGC was fitted with two distinct heater types during its short production run, and identifying which type is fitted is essential when ordering replacement parts. The changeover occurred at chassis numbers 2063 (Roadster) and 2603 (GT) for the early type, with the late type fitted from chassis numbers 2064 (Roadster) and 2604 (GT) onwards.
Early Type Heater
The early heater is very similar in appearance and construction to the MGB heater, with one significant difference: the heater water valve is directly attached to the heater matrix by being screwed to a bracket on the front of the heater casing. This water valve is unique to the early MGC, it is not the same as the MGB item. An MGB heater matrix may be used in an early MGC heater following slight modification. All other heater unit parts, the casing, blower motor, fan, and associated hardware, are the same specification as the contemporary MGB.
Late Type Heater
The late heater, fitted from the chassis numbers above, is exactly the same as the MGB heater unit, the water valve is no longer attached to the heater casing and is instead mounted separately on the engine cylinder head. However, the late-type water valve itself is not the same as the MGB item and remains MGC-specific. An alternative water valve is available, though this requires modification for correct fitment. The valve mounting bracket, clamping screw, and associated hardware are specific to the late MGC installation.
Heater Hoses and Control Cables
The heater water inlet and outlet hoses are MGC-specific. The original moulded hoses for both early and late heater types are no longer available and have been superseded by hose sold by the metre, which is cut to the correct length during installation. Jubilee or Supergrip wire clips secure the hoses at each connection point. The heat control cable is specific to the MGC, while the air control cable differs between right-hand drive and left-hand drive cars.
The cables are not shared with the MGB. Trunnion and screw kits for the cable connections are available, four are required per car.
Smiths Heater and Fresh Air Unit
The Smiths combined heater and fresh air unit draws air through a vent fitted on the scuttle ahead of the windscreen. The heater matrix and blower fan are housed in a single casing mounted at the rear of the engine bay. Two controls in the cabin regulate air distribution and temperature, with a separate switch for the heater blower motor. No MGC was ever fitted with air conditioning from the factory, though aftermarket systems were occasionally installed on USA-market cars before delivery.