I change my thermostat because the heat i was getting was very low. However i changed it and its hot but when the car is moving the heat disappear and all the cold air from the outside come through vents. Any help is appreciated.

 

Make sure you bleed the cooling system correctly. Sounds like air trapped

 

What is the suggested way to bleed the system. I ran the system on hi and remove the coolant cap.

 

Maybe a dumb question, but have you rechecked the coolant level? After using the car the level might still drop and if too low, no heat.

 

Not dumb question and it was the first thing I check before changing the thermostat