Dodge: repair/replacement heater core, engine coolant antifreeze, heater hoses

Question
Thank you for your prompt reply.  Is it necessary to pull/replace the AC dryer and "O" ring? when replaceing/repairing the heater core?-------------------------
Followup To
Question -
1995 Dodge Dakota Sports V6,automatic,AC, no PW, non working cruise control. There was a puddle of water on the passenger side of the truck. Everything in the surrounding areas was dry including the passenger seat. Truck was overheating, fluid was draining underneath truck. (I would say aprox area where the console is located ) was told the heater core needs to be replaced.  What is the determining factor that it is the heater core? What are the procedures for replacing/repairing the heater core? And any other information you are willing  to share.  Thank you
Answer -
Is it water or engine coolant (antifreeze) that is leaking? If it is water, it may be the A/C condensation just dripping. If the truck is loosing coolant, it may be the heater core because the heater core utilized the engine's heated coolant to transfer cold air into hot/warm air. Check your heater hoses that run to the firewall and then inspect the heater core. Location varies from vehicle to vehicle but if you follow the 2 heater hoses (inlet and return) the core is usually just behind the hose location on the firewall. To replace you have to remove the hoses that run to the firewall to drain the core and then follow the procedure in a repair manual for removal/replacement of the actual unit/core. I'm not sure if you have to take the dash out because this procedure varies from vehicle to vehicle. Let me know what you think and how you make out.

Rich

Answer
Well if you are diagnosing the heater core, the evaporator core does not get touched. They are two seperate units. The heater hoses that follow to the firewall should give you a general idea on the whereabouts of the heater core unit. It will be behind the firewall as will the A/c evap. core, but make sure it is the heater core. If you remover the evap core, yes you will need to replace the o-rings as well as get the system evacuated asap due to the chemical reaction from the R-134a and our atmosphere which turns it to acidic. In laments terms, your A/C o-rings throughout the system will be at risk for deteriation. You will need a gallon of 50/50 antifreeze, check the heater hoses for cracks and interior condition as well as the hose clamps before removal. After you remove them you will have drained your heater core of antifreeze and you will be ready to remove it. Like I said, that procedure varies from vehicle to vehicle. Let me know if you need more info.

Rich