my 97 outback overheats

[aschaffino]

hi auto world i have a little problem with my 97 outback.
i bought the car for 850 and was told by the buyers mechanic it had a bad head gasket. i said cool no problem. i bought the car and a had a friend re do the engine. spent about an extra 700 dollars to redo all gaskets and seals. the problem is that when i drive the car it heats up but when i turn the heat on the temperature drops right away. there are no bubbles in the radiator or any indications of a leaking head gasket. the only thing i can think of if this is a fan problem.
NEED HELP PLEASE THIS IS MY SCHOOL DRIVER
THANK YOU

[typesix]

The heater core could be plugged. Another possibility is air in the heater lines that need to be purged.