I believed I tried everything and the heater still blows cold air.
1) Made sure the heater control was moving the heater valve open and close positions. That worked.
2) Bled the the system.
3) Moved thermostat and check it. It was working. Replaced it any way.
4) Disconnected heater inlet and outlet hose and hook a water hose directly to the inlet. Then turn on water to see if the heater core had a blockage. Water did come out the outlet hose.
I did a H22 swap a year ago but I had this problem with the old engine.What any I missing? Need help.

 

Do the heater hoses under the hood get hot? Both of them?

 

Yes both hose do get warm.

 

OK since the hoses are hot that means the core is also hot. The problem is probably the "air door" that diverts air around the heater core when the dial on the dash is set to cold, and directs it thru the core when set to hot.

 

Thanks I'll look at that. Makes sense.