Answer to "Heater core replacement on a 2003 hummer h2"In case someone else comes along and sees this the above answers are incorrect. The metal heater core coming out of the firewall has these plastic connectors that the hose attaches to. The plastic connector is easy to replace and costs about $6 and the quick disconnect tool is about $9 from any local auto parts store. You do NOT need to replace the heater core or tear apart the dash to replace the plastic connectors that the hose attaches to. Takes about 30 minutes if you take your time.