one day my car busted the heater hose that goes from the firewall around the oil filter to the block. It got pretty warm but I didnt let it go to the top where the H is I Turned it off. And got a ride. Then I came back and replaced the hose and put some water in it and drove away, then I noticed that my heater doesnt work all the time. Some times it just blows cool air. And that the reseve coolant is always bubbline. And my top was steaming so I canged the top that helped a littlebit. Then I replaced the Thermostat and I have the same problem. And I kno its not the Water pump because I just bought it from mazda trix two weeks ago. So what could it be? And all my hoses are new and tight no leaks anywhere.

 

Did you bleed the system? when you add coolant to an empty you need to have the heater on. You say the heater hose blew, but if the valve was not open you did not refill the heater core. Try running the car with the heat on and the radiator fill off, when the thermostat opens you may see that the coolant level drops. Fill it according to procedure. If it keeps bubbleing in the coolant resevoir you may have a blown coolant seal...