I would check for air in the system. In advance, loosen one of the heater core hoses at the cowl so it will come off easily; reinstall and retighten the clamp. Also remove the radiator cap. With the heater control on heat + all the way to the right for hot to allow coolant to go to the heater core, start the car and get it up to operating temperature so the thermostat opens. Wear leather gloves, eye protection and long sleeves so you avoid a burn from hot coolant. Now gently slide or twist off the heater core hose you originally worked with just enough so fluid or air can escape - barely a crack is all that is needed. You may get coolant coming out right away, you may get a delay with air escaping. Once coolant starts coming out the hose, slide the hose back on and retighten. Since the radiator cap is off, the system is not under pressure so you should not get a big spurt of coolant but just be careful, keep your face out of the way and expect it just in case.
With the emergency brake set, now jack up the front of the car as high as possible. Since the radiator cap is off, any more air should work its way to the open neck. You may see bubbles when doing this. Top off the coolant if it is a little low. Then put the cap on and hose down any spills that may have occured.
The point of all this is to get air to travel to the highest points of the cooling system so it can escape. These are almost free tests. Just be careful with hot coolant. It is hotter than McDonald's coffee and does not feel good in any way on your skin.