'95 Buick Regal GS has no heat but gets luke warm and when its above 50 the heat works great, only when its cold out no heat.

Could be a number of things. Check the heater control valve that lets water flow to the heater core. This is located in the heater hose under the hood, usually with a vac. line attached to it. Make sure the engine is reaching operating temp. If not change the thermostat. If you do change the thermostat go ahead and flush the system using pure water. Loosen the draincock located at the bottom of the radiator to allow the old coolant to drain. Start the car, turn on the heater and place in the hot position. Remove the radiator cap and run water through the system till is runs clear. Do not let the level of water in the radiator run very low during the process as the engine will overheat. Shut down the car and let water drain. Tighten the draincock. Replace with 50/50 mix of coolant and water. Hope this helps. JW

Thanks, I'll try it. Mike

Hope it helps you!