I need some help with a heat problem. The hoses going into and out of the heater core feel almost cold to the touch. I thought at first the heater core was plugged but after disconecting them and putting the garden hose on them water runs thru with no apparent problem. Very Hot water comes out of the hoses when they are disconnected. but when I reconect them still no heat and they are not "Hot" like the other hoses that ciculate the water.