The Classic Mini heater draws hot coolant from the engine through a separate circuit to a small heater radiator (matrix) mounted inside the car beneath the dashboard. An electric blower motor forces air through the matrix and into the cabin via demister vents. A heater control valve regulates coolant flow through the matrix, providing variable heat output controlled by a cable from the dashboard. While the basic operating principle remained the same throughout production, the heater assembly, its control valve, hose routing and associated components changed significantly across production.
Heater Assemblies
Three distinct heater assembly types were fitted across production. The early metal-cased Smiths heater (up to 1984) has heater water hose connections 6 inches apart with ½-inch diameter fittings.
The revised metal-cased Smiths heater (1984 to 1992) has connections only 2 inches apart with 5/8-inch diameter fittings. From 1992 onwards, a plastic-cased heater replaced the metal type, with two variants, a single-speed fan version (1992 to 1996) and a two-speed fan version (1997 onwards). Each type uses its own specific matrix, blower motor, inlet/outlet pipe kit, fan switch and control panel.
Heater Control Valve
The heater control valve position changed through three distinct locations across production. Up to 1988, the valve was mounted on the cylinder head.
From 1988 to 1996, it moved to an in-line position in the engine bay heater hoses. From 1997 onwards on MPi models, the valve moved again to an in-line position within the passenger compartment hoses.
Heater Hoses
Heater hose routing and diameter changed with each valve position and engine type. Cars up to 1984 used ½-inch hose.
From 1984 to 1988, 5/8-inch connections were introduced, but the original stepped-diameter hoses are no longer available, stepped connectors with separate ½-inch and 5/8-inch hose sections provide the replacement solution. From 1988 onwards, 5/8-inch hose is standard. Hose configurations differ between 998cc carburettor, 1275cc Cooper carburettor, non-Cooper 1275cc carburettor, SPi and MPi models.
Demister Vents
Demister duct diameter changed from 1¼ inches (up to 1992) to 1¾ inches (1992 onwards), the two sizes are not interchangeable. Eyeball fresh air vents are available for both standard fascias and fascias fitted with veneer or alloy dashboards.
MGOC Spares Range
The MGOC Spares Classic Mini heater range covers complete heater assemblies for all three types, heater matrices, blower motors, fans and clips, fan switches (single and two-speed), heater control valves for all mounting positions, control cables with motif inserts, heater hoses for all engine and fuel system variants, stepped connectors, hose clips, bulkhead grommets, inlet/outlet pipe kits, demister ducts and hoses, eyeball vents and housings, air distribution boxes, heater control panels, fan speed resistors, and all associated seals and fixings.