I have a '74 challenger with a '71 340 built a couple of years now. No leaks of antifreeze, no mix in the oil,no oil in the radiator, no steam showing anytime. Running temp. is 175-180. Has a/c, 26in. radiator, new hoses, new cap. The top hose is soft almost all the time at operating temp. Once in a while the top hose will pressure up. Any help?