Cannot get the heater to work

If the heater core were leaking coolant, the fluid on the floor would be oily not clear.
When the engine is warmed up, are both heater hoses hot ?

1 check,Feel the heater hoses,do they get hot ,both or one?They should be hot,if not flush the heater core directly with a hose,back and forth at each hose connection.
2nd check,clamp off the top rad hose and force the hot water through the heater and check heat output.If there is heat with top rad hose clamped change the thermostat,it's either leaking or defective,new or not.

check to see if there is plenty of antifreeze in radiator , may have a air bubble in system .

Regarding this types of problem,i suggest you to go through this help links.Click the link below to go through the procedure and troubleshoot the problem :----

HOW TO REPLACE AN UPPER RADIATOR HOSE

http://schematicsdiagram.blogspot.com/2011/07/how-to-replace-upper-radiator-hose.html

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HOW TO REPLACE A LOWER RADIATOR HOSEhttp://schematicsdiagram.blogspot.com/2011/07/how-to-replace-lower-radiator-hose.html
----------How to Flush Heater Core?http://schematicsdiagram.blogspot.com/2011/12/how-to-flush-heater-core.html
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For heater core replacing procedure. I suggest you to go through this related help links.Its all complete step by step procedure: ----How to replace heater core for All car models?

Click the link below: ---

http://technoanswers.blogspot.com/2011/11/how-to-replace-heater-core-for-all-car.html

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How to Flush Heater Core?

http://schematicsdiagram.blogspot.com/2011/12/how-to-flush-heater-core.html

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How to Remove Heater Core ?

http://howtobyme.blogspot.com/2011/12/how-to-remove-heater-core-on-2008-honda.html
Heater Core Replacement?

http://howtobyme.blogspot.com/2011/12/honda-heater-core-replacement.html

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To replace heater core?http://technoanswers.blogspot.in/2012/02/how-to-replace-heater-core-on.html------

How to replace heater core?http://technoanswers.blogspot.in/2012/02/how-to-replace-heater-core-on_10.html
How to replace heater core on Buick Regal?

http://howtobyme.blogspot.in/2012/02/how-to-replace-heater-core-on-buick.html
----------This will help.Thanks.

Flapper door inside duct work not allowing air flow to heater core

Feel the 2 tubes at the firewall for the heater core. If they are not getting hot, the heater core needs to be flushed out or replaced. I had this problem with a 1990 Cadilac Deville, it was just a plugged up heater core.

Remember to install sealant after flushing out the system to prevent leaks.

vacuum line not closing the flapper door or the heater control valve may be bad check the hoses and see if both are hot where they enter and exit the heater core

the problem maybe heater core stopped-up. need to see if coolant is flowing thru heater core.and check to see if heater hoses are getting hot near heater core . if take off heater hoses to core with water hose run water thru one side of the hoses to see if water flows thru the other hose.

In many cars there is a flapper valve in the ductwork which is sometimes vacuum actuated.If this flapper is stuck or the vacuum line is unhooked or deteriorated,you will not feel any warm air at the vents.Look under the dash for rubber vacuum lines or try moving the selector knob for HOT/COLD or FEET/VENT/DEFROST while revving engine alittle to increase vacuum.

had same problem need to flush out the heater core .. plus make sure you do not have a air pocket in the coolant system after you changed the T-stat