The MGB oil cooler is mounted in front of the radiator, with connecting pipes passing through the diaphragm panel to the right of the radiator and running to the oil filter housing and cylinder block on the engine. An oil cooler helps maintain the engine oil at a stable working temperature, reducing thermal degradation and preserving the oil’s lubricating properties, particularly important during sustained hard driving, in warm weather, or on modified engines that generate more heat than standard. The oil cooler was fitted as standard on export MGBs from the start of production, but remained an optional extra on home market cars until the arrival of the five main bearing 18GB engine in October 1964, when it became standard across all markets. The oil cooler was also fitted to all MGC and MGB GT V8 models.
The original oil cooler was replaced by an improved intercalary construction type in January 1964. Home market cars received this improved type when the cooler became standard fitment, while export cars were subsequently fitted with a 13-row cooler from August 1965. Larger capacity coolers, in 16-row and 19-row sizes, are available for modified engines, cars used in competition, or those driven regularly in very hot climates where the standard cooler may not provide sufficient oil cooling.
Oil Cooler Kits
Complete oil cooler kits are available for four main production configurations: 3-synchro gearbox chrome bumper cars (1962 to 1967), 4-synchro gearbox chrome bumper cars (1968 to 1974), early rubber bumper cars (1974 to September 1976), and late rubber bumper cars (September 1976 onwards). Each kit includes the cooler and the correct hoses for the application.
For early rubber bumper cars, the kit should be assembled from the individual components listed, as a pre-packaged kit does not cover this specific configuration. The oil cooler hoses are available in both standard rubber and stainless steel braided options, sold individually or as pairs. The hose routing differs between the four production configurations, and the hoses themselves are not interchangeable between them, the connection points at the oil filter housing and cylinder block changed across the engine range. Stainless steel braided hoses offer improved durability, heat resistance, and a cleaner appearance in the engine bay compared to standard rubber.
For cars not fitted with an oil cooler, a bypass pipe routes oil directly between the filter housing and the cylinder block. This pipe should be retained on cars without a cooler to ensure correct oil circulation.
Oil Cooler Thermostat & Mounting
An oil cooler thermostat is available for owners who want to prevent overcooling of the engine oil in cold weather. It fits into the oil cooler pipe circuit and prevents oil from flowing through the cooler until a set temperature is reached, ensuring the oil warms up quickly to its optimal operating temperature. Fitting requires the oil cooler pipes to be cut to accommodate the thermostat body. The oil cooler mounting hardware, screws, spring washers, and plain washers, together with the pipe straps, clamp plates, and rubber mounting grommets are all available individually.
When renewing the oil cooler or hoses, the mounting hardware should be inspected and renewed where corroded, as the cooler’s position in front of the radiator exposes it to road spray, salt, and debris. The MGOC Spares range covers oil coolers, complete cooler kits, rubber and stainless braided hoses, bypass pipes, thermostats, and all associated mounting hardware for every MGB configuration across the full production run.