I recently had a new Cylinder Head fitted on my 4 X 4 X Challenger, but after two weeks it over-heated. Since then I have had a new water pump fitted and a new radiator., but it is still putting water into the header tank and even though it doesn't over-heat, I still seem to be putting 1ltr of water in if I travel 50miles or more. I usually do around 70mph +. Could the head have been damaged again when it first over-heated.