93 Bird , no heat-blows fine

A friend of mine had his daughters car at some shop because the rad blew up , not sure how bad , anyways they put in a new one and a t-stat now the thing barely blows warm , started out no heat at all , but now its just warm. The temp. gauge barely even comes up , just slightly , it seems to be air locked , is there some sort of bleeding proceedure , or is it possibly a head gasket. Does anyone know of a way to check without a pressure tester ? I guess I should say its a 93 with a 2.0L

Have you checked the heater hose flow control valve operation, pulled the heater hoses off of the heater core and tried flushing the heater core, checked with the shop to see if they put a 195 degree thermostat in it ? Normally air in the cooling system will cause the vehicle to overheat not run colder.

Just some thoughts.