Water leaking from the housing were the heater eliment is located

Sometimes, not the heater coil...this leak usually smells inside the cabin...can you see anti-freeze build up anywhere? These motors are more prone to a water pump leak (needs replaced, inexpensive and not to difficult) or the intake manifold gasket...more costly about $400. for a mechanic to do...you should see some anti-freeze build up around the intake bolts...this assumes that there is no water in your oil...which is far more costly as this indicates an internal cylinder head leak...Could be just a hose leak...a bad radiator cap...or thermostat housing leak, (maybe a cracked housing? Help me help you...do you see any anti-freeze build up anywhere? Hope this helps.

your can try flushing the system but it would be better just to change the heater core out! Instructions below
Inspect/Replace If it is necessary to remove the heater assembly, the cooling system must be drained before removing the heater core.
When a heater core leaks, a new heater core is installed or the old one repaired.
Heater Housing

• The heater housing is usually under the dash and must be removed to gain access to the heater core.
• Procedures for replacing the heater core vary with the year, make, and model of car. It threfore necessary to consult the manufacturer's repair manuals for the proper procedure for replacement.

The heater housing is disassembled to get to the heater core.
Heater Core

• Remove the access panels(s) or the split heater/air conditioning case to gain acess to the heater core.
• Remove the heater coolant hoses.
• Remove the cable and/or vacuum control lines (if equipped).
• Remove the heater core securing brackets and/or clamps.
• Lift the core from the case. Do not use force. Take care not to damage the fins of the heater core when removing.
• To reinstall the heater core, reverse the removal steps.

When the heater core leaks and must be repaired or replaced, it is a very difficult and time-consuming job primarily because of the core's location deep within the firewall of the car. For this reason always leak test a replacement heater core before installation.!

You will have to change it out!
If it is necessary to remove the heater assembly, the cooling system must be drained before removing the heater core.
When a heater core leaks, a new heater core is installed or the old one repaired.
Heater Housing

• The heater housing is usually under the dash and must be removed to gain access to the heater core.
• Procedures for replacing the heater core vary with the year, make, and model of car. It threfore necessary to consult the manufacturer's repair manuals for the proper procedure for replacement.

The heater housing is disassembled to get to the heater core.
Heater Core

• Remove the access panels(s) or the split heater/air conditioning case to gain acess to the heater core.
• Remove the heater coolant hoses.
• Remove the cable and/or vacuum control lines (if equipped).
• Remove the heater core securing brackets and/or clamps.
• Lift the core from the case. Do not use force. Take care not to damage the fins of the heater core when removing.
• To reinstall the heater core, reverse the removal steps.

When the heater core leaks and must be repaired or replaced, it is a very difficult and time-consuming job primarily because of the core's location deep within the firewall of the car. For this reason always leak test a replacement heater core before installation.

If it is necessary to remove the heater assembly, the cooling system must be drained before removing the heater core.
When a heater core leaks, a new heater core is installed or the old one repaired.
Heater Housing

• The heater housing is usually under the dash and must be removed to gain access to the heater core.
• Procedures for replacing the heater core vary with the year, make, and model of car. It threfore necessary to consult the manufacturer's repair manuals for the proper procedure for replacement.

The heater housing is disassembled to get to the heater core. Heater Core

• Remove the access panels(s) or the split heater/air conditioning case to gain acess to the heater core.
• Remove the heater coolant hoses.
• Remove the cable and/or vacuum control lines (if equipped).
• Remove the heater core securing brackets and/or clamps.
• Lift the core from the case. Do not use force. Take care not to damage the fins of the heater core when removing.
• To reinstall the heater core, reverse the removal steps.

When the heater core leaks and must be repaired or replaced, it is a very difficult and time-consuming job primarily because of the core's location deep within the firewall of the car. For this reason always leak test a replacement heater core before installation.

Inspect/Replace If it is necessary to remove the heater assembly, the cooling system must be drained before removing the heater core.
When a heater core leaks, a new heater core is installed or the old one repaired.
Heater Housing

• The heater housing is usually under the dash and must be removed to gain access to the heater core.
• Procedures for replacing the heater core vary with the year, make, and model of car. It threfore necessary to consult the manufacturer's repair manuals for the proper procedure for replacement.

The heater housing is disassembled to get to the heater core. Heater Core

• Remove the access panels(s) or the split heater/air conditioning case to gain acess to the heater core.
• Remove the heater coolant hoses.
• Remove the cable and/or vacuum control lines (if equipped).
• Remove the heater core securing brackets and/or clamps.
• Lift the core from the case. Do not use force. Take care not to damage the fins of the heater core when removing.
• To reinstall the heater core, reverse the removal steps.

When the heater core leaks and must be repaired or replaced, it is a very difficult and time-consuming job primarily because of the core's location deep within the firewall of the car. For this reason always leak test a replacement heater core before installation.

check your water pump for leaks. If its coming for the pump housing it will need to be replaced. Check the gasket area where the pump bolts to the block.. If water is not from the pump or around it check your hoses and clamps. check thermostat housing.

Your HVAC BOX is Filling up Due to a Glogged Drain tube, UNDER PASS SIDE THERE IS A RUBBER STEM THAT A PENSIL OR SOMETHING LIKE IT SHOULD BE POKED INTO THE TUBE TO UNCLOGG IT

Here is the steps for the removal and replacement...getting you the picture and location next. 6.6L Engine

1. Disconnect the negative battery cables.
   
2. Drain the fuel from the fuel filter as follows:
   
   • Install a hose on the water drain on the water-in-fuel sensor.
     
   • Place the other end of the hose into an approved container.
     
   • Drain as much fuel as possible from the fuel filter housing.
     
   • Tighten the water drain on the water-in-fuel sensor.
     
3. Remove or disconnect the following:
   
   • Water-in-fuel sensor harness connector
     
   • Fuel filter from the fuel filter/heater element housing
     
   • Water-in-fuel sensor from the fuel filter
     

Exploded view of the fuel filter (2)—6.6L engine

To install:

1. Install or connect the following:
   
   • Water-in-fuel sensor in the fuel filter
     
   NOTE Check the fuel filter/heater element housing and the filter for a dislocated filter seal or foreign debris. Contamination on the filter/heater housing may cause leakage at the fuel filter. Coat the seal with clean engine oil.
   
   
   • Fuel filter on the fuel filter/heater element housing
     
   • Water-in-fuel harness connector
     
   • Negative battery cables
     
2. Prime the fuel system:
   
   • Pump the primer located on top of the fuel filter 30 times or until stiff.
     
   • Try to start and run the engine. If the engine does not start, repeat the previous step.
     
   • Allow the engine to run for 5 minutes at idle.
     
   • Check for fuel leaks and clear all Diagnostic Trouble Codes (DTCs).
     

Check your water outlet housing. It's plastic, the thermostat sits on top of it.

This sure sounds like the AC condensate drain is plugged, if it is allot of condensation water builds up in the heater/AC case and leaks in on the passenger side, the drain is located on the pass side under the hood down low on the firewall, it is most cases it is a rubber nipple about 1/2 inch in diameter sticking out of the firewall with a little flapper valve in it, stick your finger in it or a stick and see if water drains out.