Help please. 316i 1995. New radiator and waterpump fitted now keeps overheating. Bled coolant system endlessly...now removed thermostat in desperation so it cant be that not opening! Pipes to top and bottom of radiator get rock hard so pressure in there way too high. Fan and switch working perfectly so not that. Really don't think it's air lock and it's not the head gasket...2 questions as I must be doing something stupid! 1) Could I have TOO MUCH coolant in there which is causing the pressure build up? 2) Is the radiator cap designed to release the pressure build up, as this hasn't been changed and may be faulty if it is supposed to do this? Any advice offered would be greatly appreciated. Thanks all!