Cadillac Repair: New Heater core no heat, warm heat, runnung

Question
QUESTION: I have a 91 Deville 4.9. I have had it for a year and there has never ben any heat. Changed T-Stat, I have tested the blend door and it is working properly. Yesterday I changed the heater core and still very little heat, luc warm after 30min of runnung. I took the restrictor tee out think it may have been played with befor I bought it, still no difference. which way should the resrictor be. I think It may be air in the heater core since it does blow warmer while driving but as soon as I stop and ilde it gets cold again. I tried getting the air out by running it with the rad cap off, and some air came out. Is there a procedure to bleed this cooling system. Any help would be appreicated

ANSWER: Other than no heat, Does the rest of the climate control panel put out air from the proper vents when you select them ?.

Does the AC work correctly and put out air from the proper vents ?.

is the proper thermostat installed in the engine ?.

Does the engine temperature reach normal operating temp ?.

Do the cooling fans at the radiator run even when the engine is COLD ?.

Are you absolutely POSITIVE that the A/C-Heater programmer arm is moving correctly when you select heat ?.

---------- FOLLOW-UP ----------

QUESTION: Yes the A/C works great out of the A/C vents, I just changed the T-stat with a 190 Degree last year, It is also working. The cooling fans never seems to come on, The programmer also fuction correctly, And I just rechecked the blend door. it moves smoothly from hot to cold but still luc warm heat at 32C.

ANSWER: What about the heater hoses when the engine is at normal operating temperature. One should be EXTREMLY hot and the other slightly cooler where they attach to the heater core at the firewall. Are they ?.

Did you blow air thru the new heater core prior to installing it just to make sure that some wise guy did not stuff his lunch bag or put something in the heater core to restrict the flow of coolnt ?.

believe me, It happens more often then you can imagine.



---------- FOLLOW-UP ----------

QUESTION: I FLUSH WATER THRU IT BEFORE INSTALLING, I USED MY LASER THERMOMETER AND THE BOTTOM HOSE IS 175F AND THE TOP 115F WITH BLOWER ON HIGH AND 125F WITH BLOWER OFF, I WAS THINKING OF PINCHING OFF THE BYPASS HOSE TO FORCE COOLANT THREW THE CORE AND PUSH OUT ANY AIR IN IT. IT IS THE FIRST CAR I HAVE SEEN WITH A HEATER CORE BYPASS, I AM SURE IF THERE IS AIR IN THE CORE THE BYPASS WOULD MAKE IT HARD TO BLEED OUT. LET ME KNOW IF YOU THINK THIS WOULD WORK OR IF THERE IS A PROCEDURE TO BLEED THIS SYSTEM. MY MITCHELL ON-DEMAND DOESN'T TELL ME MUCH.

Answer
There is no special procedure to purge air from the system.

I still think that your PROGRAMMER is NOT opening the damper door vent in the heating duct to allow heat to pass thru the core.

Try this:

1. Unsnap the threaded metal rod from the plastic clip on top of the programmer assembly behind the glove box and with the engine at normal operating temp, Set the climate control for full heat and then PULL the threaded rod TOWARDS you and see if you now get heat.

If you now get heat, wait 3 minutes for the programmer arm to finish it cycling and then snap the metal rod back onto the plastic clip.

You already proved that you have water to the heater core by the hose temps.