The C-series six-cylinder generates substantially more heat than the MGB's four-cylinder unit, making effective oil cooling essential for engine longevity. Engine oil serves as both lubricant and heat-transfer medium, carrying heat away from the bearings, piston rings, and cam followers to the oil cooler where it is dissipated to the airstream. Without adequate cooling, oil temperatures rise past the point where the lubricant maintains film strength, accelerating bearing wear and risking outright bearing failure. The MGC oil cooler system is entirely different from the MGB's in capacity and configuration, reflecting the greater thermal demands of the six-cylinder engine.
Engine Oil Cooler, Manual Gearbox Cars
Manual gearbox MGCs use a sixteen-row engine oil cooler, mounted in front of the radiator with the connecting pipes passing through the radiator diaphragm panel. The cooler is positioned to receive the full benefit of ram air at speed, and the sixteen-row capacity provides substantial cooling surface area for the volume of oil circulating through the C-series engine. Complete oil cooler kits are available including the sixteen-row cooler, a pair of hoses (choice of rubber original or stainless braided alternative), connections, and fixings. The kit fixings may not all be the same as those used with the original factory-fitted MGC oil coolers, this reflects the ongoing evolution of available components, but the kit provides everything needed for a complete installation.
Individual engine oil cooler hoses, both long and short, are available in rubber or stainless braided specification, along with the hose grommet, hose strap kits, adaptor, and sealing washer.
Oil Coolers, Automatic Gearbox Cars
Automatic gearbox MGCs use a smaller ten-row engine oil cooler alongside a separate seven-row gearbox oil cooler, two distinct cooling circuits serving different requirements. The automatic gearbox generates significant heat in the torque converter fluid, particularly during urban driving where the converter is slipping frequently, and the separate gearbox oil cooler is essential for maintaining transmission fluid temperature within acceptable limits. Overheated automatic transmission fluid degrades rapidly, causing varnish deposits on internal components, accelerated seal wear, and ultimately transmission failure. The gearbox oil cooler connects via dedicated short and long pipes with adaptors, and rubber or stainless braided hoses.
The mounting bolts differ between manual gearbox (engine oil cooler only) and automatic gearbox (both engine and gearbox coolers), as the automatic installation requires longer bolts to accommodate the additional cooler brackets. When ordering an oil cooler kit, the gearbox type, manual or automatic, must be specified, as the kits are different.
Alternative Cooler Sizes
For owners seeking different cooling capacity, alternative oil cooler sizes are available: a thirteen-row cooler as a general alternative where the full sixteen-row capacity is not required or where space is constrained, and a nineteen-row cooler for tuned engines, cars used in competition, or operation in very hot climates where the standard sixteen-row unit may be insufficient. The nineteen-row cooler is a popular upgrade for Stage 2 engines, where the increased power output generates proportionally more heat that must be dissipated effectively.
Hose Selection and Maintenance
Oil cooler hoses are available in two materials: standard rubber and stainless steel braided. Rubber hoses are the original specification and provide reliable service when replaced at regular intervals. Stainless braided hoses offer a significant upgrade in durability, heat resistance, and burst strength, the braided outer layer contains the hose under pressure and prevents the ballooning that eventually causes rubber hoses to fail. Stainless hoses also resist abrasion better than rubber.
Inspect oil cooler hoses at every service for softening, cracking, chafing, and weeping. A failed oil cooler hose causes rapid and total oil loss, the engine oil pressure drops to zero within seconds, and continued running even briefly will cause catastrophic bearing damage. Hose strap kits secure the hoses to prevent chafing against the radiator, bonnet lock platform, and other engine bay components. The hose grommets where the pipes pass through the diaphragm panel should be replaced if perished, as they prevent chafing at this critical transition point.