I have a 1991 buick regal and when i turn the heat on only cool air blows out. it doesnt leak on floor either as if heater core was out. what should i do

Third post of same question? Check air door actuator, vacuum leaks, bad check valve.

Blend door actuator stuck or vaccume came dissconected. Or could be low on coolant and not getting flow through the heater core

if it doesnt switch you may have a vaccum leak, but i work for a junk yard and we seel alot of heater controls for this car you may want to get a new or used one from a junk yard

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

--------------
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.

REMOVE OR DISCONNECT

1. Negative battery cable.
2. Drain cooling system.
3. Upper firewall weatherstrip.
4. Upper secondary cowl.
5. Heater hoses from core.

NOTE Blowing out residual coolant from inside the heater core will prevent coolant leakage into the passenger compartment when the heater core is removed.

1. Sound insulator.
2. Rear seat duct adapter.
3. Heater duct.
4. Heater core cover.
5. Heater core.

INSTALL OR CONNECT

1. Heater core.
2. Heater core cover.
3. Heater duct.
4. Rear seat duct adapter.
5. Sound Insulator.
6. Heater hoses to core.
7. Upper secondary cowl.
8. Upper firewall weatherstrip.
9. Fill cooling system and check for leaks.
10. Negative battery cable.

No there is not, they did not put cabin air filters in their cars until 1997.

the resister only changes the fan speed
if you have not heat
first check coolant level if it's down then you have a leak that will cause no heat if it's ok
then run the vehicle and make sure the engine temp gauge reads about half if not change the thermostat if the engine temp is ok
then grab the heater hoses see if they are hot then the heater core is plugged and if the heater hoses are hot
then there is a problem with the heater control head
hopr this helps

The heater core inside the passenger compartment is leaking. The water is draining through the Air Conditioner condensor drain tube. Don't plug the drain tube, the passenger side floor will get wet.

First, drain cooling system (or be quick) and disconnect the two heater hoses that are going into the firewall and splice the ends together with a 5/8" garden hose splicer.
The leak will stop, but your heater will not heat the interior.

Replace the heater core....

air lock in small radiator for heater

I had this problem twice and it probably is the heater core. There is a temporary fix if you can't get it changed out right away. You can get it tied off but you won't have any heat, it will stop leaking though. Does your heater work? If your heater blows cold and only blows warm when your car warms up then starts blowing cool air again that's a surefire sign.