I have been having trouble with my heater. When set to the hottest position its hardly warm. The coolant is clean, the heater hoses are hot, I did a heater core flush when I did a cooling system overhaul, the blend door cable/linkage isn't broken.

The water pump, radiator, t-stat, hoses, radiator cap are all maybe 7 months old. Any help would be greatly appreciated. Thank you.

 

Verify temps with an IR heat gun?

 

Did you back flush the heater core ? you need to flush the heater core both ways and when you get done , do it all over again .