Redog

1985 Delta 88

I have replaced the thermostat, HC, switched some vacuum lines around that where incorrect (purple Hose to vacuum ball, was to mani) an the gray tube to the heater control valve makes vacuum when the selector is on cold, and not when on hot.

Heater control valve is stuck in the mani. I couldn't budge it, my mech couldn't budge it, so I hope that's OK

The heater core door (next to the core) works. I took pics of it open and closed. However I've never heard the heat door slam open like I did on my old delta. I want to check that next.

Where is the access to it in the dash? Is it behind the glove box? How does it work? Vacuum controlled? I took out the HVAC controls and everything was connected.

Any ideas? Am I on the right track?

Redog

Oh yeah, the valve and heater hoses do get hot!

Redog

Really? Nobody knows?

I did some digging on break. Took out the glove box and there was a silver door with a round almost flat disk in front of it. It has a vacuum rubber hose hooked up to it ( didn't check for vacuum there, ran out of time ). This door opened pretty easy (not stuck) when I pushed it.

Setting was to "hot" but still didn't feel any hot air. Antifreeze is. Very low (just had car flushed) so I'm going to top that off tomorrow after the car is cold and all the pressure is gone. At this point it was at idle for about 15 minutes.

Sound like a heater control valve? Am I looking in the right place? Come on, somebody has to know this!!

rustyroger

When did you last use the heater?, if you haven't used it since last winter it does seem likely something has stuck.

The heater hoses getting hot doesn't mean the valve is opening fully, but vacuum controlled doors might equally be the cause, you might even have more than one problem.

I'm not familiar with '85 Deltas but can you get your fingers in to the heater matrix?, it should be very hot to the touch.

Give us all the information you have (when the problem occurred, was it gradual or sudden etc), the more information we have the better we can help.

Roger.

rocketraider

Is it Tempmatic or regular airconditioning?

Lady72nRob71

If manual, check were the temp lever cable attaches to the temp door in the heater box. That attaching point often breaks.

oldcutlass

Get a pipe nipple and remove the hoses from the heater control valve, insert nipple between them and clamp them down. That will eliminate anything interfering in the water circuit.

Redog

I bought th car in April, knowing tit had on heat

Redog

Regular ac

Redog

The door next to the core works fine. I was playing with that when I replaced the core.

Lady72nRob71

Most of these heater valves are failsafe, meaning it takes vaccum to close them. This way should they become stuck while sitting, they will get stuck open.
If the in and out at the heater core connections are the same temp, the coolant should be flowing through. If you have in IR thermometer, you can check this easily. Otherwise, check with your hands, a few minutes after a cold startup (less heat-soak error).

Redog

They do have a IR thermo here at work! I'll try that on one of my breaks tonight!

Redog

Nope the IR thermo is now locked up at nite. Oh well

Lady72nRob71

Just check with your hands, a few minutes after a cold startup (for less heat-soak error)