81 eldorado heater

[Joel]

my 81 eldo blows air but wont get hot. it did a few months ago and just quit. i checked the coolant and replaced the thermostat. Is my problem the heater core? and where is it located.

[doug]

While its a possible heater core problem (lets hope it isnt), it could be your heat control valve.  While Im not exactly sure on your car, there should be a valve along the heater hose near the firewall or on the back of the block.  First thing to do is check to see if the vacuum hose is connected and not split at the end (if so, clip it with a pair of scissors).  You might also try following it inside to the switch and do the same thing.  If that all looks OK/doesnt work, I would try eliminating the valve and bypass the hose.  If that works youve got a bad valve.  For good measure, you should also thoroughly flush the entire system, focusing on the heater core.  Perhaps others have had the problem?  I guess youve got the V-8-6-4?  Hows that working for you?  Good luck.

[denise 20352]

  Feel both heater hoses.  If they are both hot, then you have coolant pumping through the core, and its time to look inside.  If its not circulating, the heater control valve may be bad.

  If you do have heat to the core, remove the glove box liner.  Behind the glove box and to the left, near the middle of the car, there is a valve inside the duct that mixes hot air into the airstream.  The lever that controls it is on the top of the box in the middle of the dash.  In an electronic system, there will be a linkage going from that valve to a programmer box that is usually mounted on the outside of the airbox, right behind the glove box.  This is probably what you have.  A manual system would have a cable going to the valve.

   Disconnect that link (if it hasnt already disconnected itself, turn on the heater and work the valve forward and back.  It should move freely.  The airflow should go from cold to hot.  When heat is on, it should be coming out the floor vent.   If moving that valve changes the temperature, then there is a problem with the mechanism, programmer box or control system that will have to be troubleshot, when you get time.  To keep your heater going in the meantime, you could always duct tape that valve open.  

-denise

[Joel Freeman]

I will give the velve thing a try. Thanks for the help. I actually have an olds 350 diesel converted to gas. It has 455 heads and a quadrajet carb/roller rockers. It runs kinda crazy but allways starts. I have an olds 403 block to go in it if i ever get around to it.

[Joel Freeman]

Thanks for the help. I will give your advice a try. Much appriciated.