text: In 1952, Jaguar, worried by a report about the speed of the Mercedes-Benz 300SLs that would run at Le Mans, modified the C-Type's aerodynamics to increase the top speed. However, the consequent rearrangement of the cooling system made the cars vulnerable to overheating, and all three retired from the race. The Peter Whitehead-Ian Stewart and Tony Rolt/Duncan Hamilton cars blew head gaskets, and the Stirling Moss-Peter Walker car, the only one not overheating having had a full-sized radiator hurriedly fitted, lost oil pressure after a mechanical breakage. Testing by Norman Dewis at MIRA after the race proved that the overheating was caused more by the revisions to the cooling system than by the altered aerodynamics: the water pump pulley was undersized, so it was spinning too fast and causing cavitation; also the header tank was in front of the passenger-side bulkhead, far from the radiator, and the tubing diameter was too small at 7/8 inch. With the pump pulley enlarged, and the tubing increased to -inch, the problem was eliminated. The main drawback of the new body shape was that it reduced downforce on the tail to the extent that it caused lift and directional instability at speeds over  on the Mulsanne Straight. These cars had chassis numbers XKC 001, 002 and 011. The first two were dismantled at the factory, and the third survives in normal C-type form.
  In 1953, C-Types won again, and also placed  second and fourth. This time the body was in thinner, lighter aluminium and the original twin H8 sand cast SU carburettors were replaced by three DCO3 40mm Webers, which helped boost power to  . Philip Porter mentions additional changes:
  Further weight was saved by using a rubber bag fuel tank ... lighter electrical equipment and thinner gauge steel for some of the chassis tubes ... [T]he most significant change to the cars were the triple Weber carburetors and [switch to] disc brakes.
  Duncan Hamilton and Tony Rolt won the race at   – the first time Le Mans had been won at an average of over .