Intake gaskets. My 3.1 beretta had the same problems. Also check the thermostat housing, water pump, but your heater core is bad, you know that, fix it! It is a leak, unless you disconnected it and put something in between the hoses on the fire wall its leaking, cuz coolant still flows through the hoses. Fix that first, then give a good look at the waterpump if its leaking youll be able to see it while the engine is idling.

I agree mith Mechanic. Do a yahoo search on bypass heater core. On my wrangler it took about 5 minutes. Your going to lose a lot of water that way. Once you bypass the heater core and you fill the radiator see if it holds and maintains coolant levels. If it does it's not your water pump.

False economy no heater core fix..low coolant level risks over heating and may have led to water pump seal failing. Edge of belt wear would suggest out of line bearings . Probably worn water pump bearings especially I after after tightening new belts.

Change pump. Fit new gasket, replace heater core.

Replace the water pump and bypass the heater core until you get it replaced.

1986 Pontiac Firebird 2.8 V6, 109,000 miles. Went to my car and there was a puddle of coolant and my radiator was nearly empty. Filled my radiator, but it still leaks when i park it. I see the coolant leak in the water pump area, people are saying it's the water pump. I just recently replaced my alternator belt and tightened my A/C and power steering belts. The alternator belt is the same size as the last one, and its been fraying slightly on the side. Could the two problems be related? Should I just get a new water pump or new seal for the water pump? Also, I've had a busted heator core for the past two years so i've had to keep the coolant level low in the coolant tank or it will spill all over my passanger side floor.