I have a 2004 landrover discovery. I have had an off and on cooling issue. Sometimes if I am climbing hills it is fine...other times it gets hot. If I bleed the cooling system properly it works for a while well, but eventually it seems to get air back into the coolant and overheats on hills. I replaced the hoses and expansion tank cap to no avail. Today I bled the system and dropped the bleed screw....lol..(can't find it gotta spend $60), and to look for it I took off the plastic grill over the radiator. I noticed that the little radiator near the radiator was dented on top. I think this small radiator thing is the heater core if I am correct. The dent hasd flattened the top of the core and flattened several baffles on the unit. 2 questions: How would it get dented on the top left corner? and Would this cause my cooling problem? Thanks in advance for help!