I've had my 1988 RX for about 4months now and everything seemed to be working fine with it but recently when i go to turn on the RX the add coolant light and buzzer go off. I've checked the radiator to make sure it had coolant and like i suspeceted it was completely full, yet when i squeezed the top hose comming from the radiator to the block it felt like it had no pressure(water) going through itbut after about4 or 5 min. of running the lights go offand the buzzing stops.Any thoughts???