98 Cavalier Coolant Leak

[bFcKyle]

The coolant leak is somewhere underneath the mid of the engine. ive check for white smoke starting the car and stopping and going but no smoke appears, i've checked the oil no mixed oil/coolant, the hoses show no leakage or cracks etc. The heat tends to not work at times even with full coolant, maybe head gasket leak? a/c condenser? If either one, estimate on the cost of repairs?

[knightmare]

Heater Core?

[bFcKyle]

thats what i was thinking since the heat doesnt effect the temp but only keeps it risen