The MGB cooling hose configuration changed during the period covered by this section, corresponding with the two radiator types used on cars with mechanical engine-driven cooling fans. Identifying which radiator type is fitted is the essential first step when ordering replacement hoses, as the top hose, bottom hose, and associated connections differ between the two configurations.
Rear-Fill Radiator Hoses (1962 to 1967)
Cars from the start of production in 1962 to the end of 3-synchro production in 1967 used a rear-fill radiator, with the filler cap located at the back of the header tank on the engine side of the diaphragm panel. On these cars, the top and bottom radiator hoses are the same length and profile. The bottom hose connects via an alloy elbow and a separate water pump-to-elbow hose. The heater circuit uses a short heater hose from a union at the cylinder head to the heater valve, with the union sealed by a washer.
Centre-Fill Radiator Hoses (1967, September 1976)
From the start of MkII production in 1967, MG adopted a centre-fill radiator with the filler cap relocated to the front of the header tank, making the coolant level easier to check when topping up. This radiator was used on all 4-synchro cars, covering 18GD, 18GG, and 18V engines through both chrome bumper and rubber bumper production to September 1976. The bottom hose on centre-fill cars is a different profile from the rear-fill type to suit the revised radiator outlet position.
Hose Kits & Upgrades
Complete cooling hose kits are available for both configurations, providing all the hoses, clips, and associated items needed for a full cooling system hose renewal in a single package. Kevlar-reinforced hose kits offer improved durability and resistance to collapse under vacuum compared to standard rubber hoses, an important consideration on older cooling systems where the water pump may generate significant suction on the intake side.
For owners seeking a long-term solution, silicone cooling hose sets are available. Silicone hoses resist hardening, cracking, and deterioration far more effectively than standard rubber over extended periods, and are supplied with stainless steel band clips. They are particularly well suited to cars that are used regularly, stored for long periods between use, or where the owner wants the reassurance of a cooling hose set that will not need replacing for many years.
Hose Clips
Hose clips are available in both worm-drive and original-style wire types, in the sizes used across the MGB cooling system. Wire clips are the correct original fitment for concours-standard restorations, while worm-drive clips offer a more practical solution for regular use, providing easier adjustment and a more positive clamping force. When renewing cooling hoses, it is good practice to flush the cooling system, inspect the radiator condition, and check the thermostat, water pump, and heater valve at the same time. Deteriorated hoses are often a sign that the coolant has not been changed regularly, and the internal condition of the system should be assessed before refilling.