So i replaced head gasket, timing chain and tensioner and got the head resurfaced recently. So I went to go bleed the coolant system and when it warmed up I started hearing a popping noise from the top radiator hose. Thermostat didn't get to open. Could it be that it's a bad water pump?

Thanks in advance

 

No, most likely air in the system and water is not reaching the thermostat. Had the same problem after replacing my head gasket. Make sure to bleed the system preferably with a filler bucket that attaches to the top of the radiator where the cap goes and let it fill with the car on with heater on for at least 20 min. Should get rid of any air.