How do i remove a heater core on a 5.7 liter motor

Not the thermostat, that is on the engine. You must have a leaking heater core- this is the small metal thing, looks like a book-sized radiator. It fits inside your heater case and is what gives you warm air from the heater. Your only recourse is to remove and replace the heater core. On older cars, this was not a big deal- the heater cores were fairly accessible under the dash. Newer cars, it's not so easy-so much stuff in the way, in many cases, the entire dash must be removed to get to the heater core. You might get lucky and it will be a simple job.
If you need to drive the car before you fix the leak, you can bypass the core by splicing your two heater hoses together. You won't have heater or defrost then, too bad it has to happen during the winter, but that is the only way to safely use the car until the leak is stopped. Don't trust Bar's leak or similar coolant sealers: Your leak is probably too big for them to work on, and those sealers often cause more problems than help.

More than likely since your heater core is by-passed,your thermostat was probaly removed and you may be without one.Here's a link to check and replace it.Here's a link to heater core.Your heater core could be bad since it was bypassed,does the front floor board have water stains anywhere.

your heater core is leaking, that would explain the antifreeze on the passenger floor-as for it leaking there when it rains, there is a piece of molding that sometimes move out of place, it is under the hood on the passenger side, below the vent plate (remove the wiper blade arms, the plate for access)-the ac not working? that could be as simple as low freon, or as bad as multiple leaks, comtaminated system, electrical issues-do you mean the blower motor, because with all that moisture stuff you have going on there I wouldn't be surprised if the blower motor has electrical issues due to the flooding.

The MOST IMPORTANT THING is to fix or bypass the heater core, or you will end up needing an engine if it overheats.

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.

1.Disconnect the cable from the nrgative battery terminal. Drain the cooling system
2.Remove the cowl vent panel, Then disconnect the heater hoses from the heater core inlet and outler tubes at the firewall.
3. on models so equipped, disconnect the engine ground strap attached to one of the heater core tubes.
4.Remove the center dash support trim and the radio cassette box ashtray.
5. Pull back the carpeting and pull the rear airflow duct away from the main floor duct.
6. Remove the two instrument panel support brackets and the heater main floor duct.
7. Remove the screws and the heater core cover, the remove the heater core. (Be careful not to tear the foam sealing material).
8. When reinstalling the heater core in the housing, make sure the original foam sealing the material is intact and in place.
9. The remainder of the installation is the reverse of removal.
10. Fill the cooling system.
Run the engine and check for coolant leaks.
Good Luck!!
Any questions please feel free to post it and I will answer it.

sounds like your heater core is leaking ,and possible you may need to change the resister for the bower motor ...have it tested for leaks ....look on passengers side on the floor ...look up with a trouble light once the motor has warmed up ,turn the blower motor on high ...and look under the hood and all around for leaks ....feel the rug on the floor on the passebnger side for wet ness ...good luck

drain out your fluid
2.near the fire wall in engine, loosen clamps and remove heater hoses from th tubes running to the core.
3. remove dash panel on inside of car(passenger side)
4. remove the duct/vent from core.
5. remove cover(screwsand clips)
6. remove core retaining straps and pull out core.
installion is reverse and watch you dont loose too much coolant on your floor. Replace and fill coolant. run your heater to make sure you have no leaks

You have a heater core leaking.The vehicle has a small radiator looking part,that the radiator fluid flows threw,and of course,is hot.The blower motor blows threw the heater core,and gives off heat.When they devellope a hole,or a crack in them,they leak.These leak into the floor board.I hope this helps you ,and if so,please let us know.Thank you.

Drain the coolant. Remove the dashboard first, then a bunch of air ducts, then the heater core cover. Remove the heater hoses in the rear of the motor, and finally the heater core.

REMOVE OR DISCONNECT

1. Negative battery cable and drain cooling system.
2. Raise vehicle and remove drain tube from heater case.
3. Heater hoses from heater core and lower vehicle.
4. Right and left sound insulators and steering column opening filler.
5. Floor air outlet duct and heater core cover.
6. Heater core mounting clamps and remove heater core.

INSTALL OR CONNECT

1. Heater core and heater core mounting clamps.
2. Heater core cover and floor air outlet duct.
3. Right and left sound insulators and steering column opening filler.
4. Raise vehicle and connect heater hoses to heater core.
5. Drain tube to heater case and lower vehicle.
6. Negative battery cable and fill cooling system.
7. Check for leaks.