canuck buick

So I have issues with my hvac. The PO previously removed the ac. I live in Canada car is a convertible so no huge deal. My heat doesn,t blow hot but cool through all vents it seems. I remove my computer sensor or whatever you call it and look in and I see my heater core and door . Door is halfway it appears. Ican push it closed with some pressure with a screwdriver through the opening. Next I see what appears to be a big stain down the middle of my core, I am guessing a leak but hoping not, though don't know what else it could be. my carpet is not wet, on the weekend I am going to take off the panel and have a closer look. does it matter which way the hoses on the fire wall are hooked up to the heater core, presently the top firewall fiting is connected to the water pump and the bottom fitting to a pipe that disappears under the engine. Mine is a C68. I would like to get the heat working so I can blow the fog off my windshield . I am guessing at maximum heat that door should be open exposing the core and at cool the door would move so you cannot see the core. Can I somehow force this so I get full heat?

I know a lot of info about but am not sure where to start.

hooked073

what is your temp running??

canuck buick

170 Just removed my hush panel and the insulation was wet ..aaagh ..nooooo I have to replace my heater core aaagh. I can also hear my blend door moving but doesn't seem to change position.

DanielRicany

Okay so when you put a new one in just remember that the flow going to the heater core should enter through the bottom and exit through the top. Heat rises.

Also, make sure to bleed the cooling system after you fill it up otherwise you will have no heat. And good luck with replacing that.

Maybe try some stop leak. Lol

Cliff Harris

This is what the blend door looks like in the maximum heat position (90° F):



You shouldn't be able to move it manually. It is moved by the blend door motor, which has a very large gear reduction. This is what it looks like from the top:



The rod going out of the top of the picture connects to the blend door. Sometimes the white button breaks, which might be the situation in your case.

You might have a problem with your HVAC programmer. It's located above the gas pedal. It controls the blend door motor. It's quite common for the two large resistors associated with the blend door motor to either burn up or cause the solder to crystalize and stop making a good connection. They are in the lower left corner of this picture of the HVAC programmer PC board:



The HVAC system does a calibration test of the blend door every time the ignition is turned on. It moves the blend door to the maximum cold position, the maximum hot position and then sets it to the position called for by the temperature setting on the HVAC control head. You can watch the system do the calibration through the opening in the top of the evaporator housing after you remove the fan speed controller. It takes about 15 seconds to do this calibration (as I said earlier, the blend door motor has a very large gear reduction, so it's pretty slow).

canuck buick

|Thx I will be going to our local parts place to see if they have or can get cores.

WW7

Which hose goes on which tube shouldn't be a problem, they are 2 different sizes......... 5/8" and 3/4"....WW

hooked073

heat is still going to be cool with an engine temp of 170. might want to put a stock stat in there also