Hello everyone im in need of a little help here.. I have a 84 Delta 88 sedan 307 engine with a 4BL carb.. Now this is my first time owning an Olds and im having problems with my heat.. Now mind you the A/C works great but for some reason when i switch to heat all i get is cold air.. I have already check the vent doors on the passenger side behind the glove box to make sure that the inside switch are opening and closing the vent doors and its working just fine.. The other things I have done are changed the radiator the thermostat and the heater control valve.. So my next steps are the heater core and the water pump since since they look pretty old.. Now the problem i ran into in buying these parts are that i'm always asked with A/C or without and since i have A/C shouldn't it be with A/C ? The reason i asked because I really don't know the answer..So could someone please shed some light on this subject for me and does it really matter?? Thanks in advance !!!

 

Yes, parts are w/ac.
Make sure you have the system good and burped
after changing the rad. You can pull a heater hose off
the top side and see if fluid is coursing. Have someone ready to
shut it down when doing this, it will be a little messy.

 

Feel of the hoses. They should be hot if coolent is circulating through them.

 

Is the coolant full?

X2 on are the hoses getting hot...do both radiator hoses (upper and lower) and both of the heater hoses get hot? Water pumps and heater cores are not usually the source of no heat, they usually leak when they are bad.

Were the radiator, thermostat, and water control valve replaced in an attempt to fix the no heat or for other reasons? Did the heat work before replacing these?

 

Does the heater control valve have a vaccum hose going to it. When "Heat" is selected, vaccum should be routed to the control valve to open it to allow hot water to flow through the heater core. The control valve is after the water has passed through the heater core.

 

Excellent hints so far.
Also were you sold the correct water control valve? Very early models required vacuum to open, later years (like '86) require vacuum to close (a failsafe). They all would physically fit in the block though.
See if you are getting vacuum to the valve (for temp lever COLD or MAX AC) and no vac for WARM or any other function.
Take a clean piece of hose, connect to valve and suck on it. If hot water flows with vacuum, you got the wrong type.

 

Thanks for the heads up Rob. I was not aware of the different valves. My daughters '70 cutlass uses vaccum to open.

 

Looks like this confirms my suspicion that the transition was around 70 and 71. My 72 uses vacuum to close the valve.

 

Okay everyone thanks for the responses.. Now to answer some of the questions that were asked... The water level is full the control valve looks totally different from the one i had to replace and yes i think it uses a vacuum.. Now i have only had the car for six months so i really can't say if it was working before purchase since it was pretty hot here in Louisiana but i was told before i purchased the car that it was working.. Now for the hoes on the heater core well only one hoes get hot and that's the one from the control valve to the heater core the other hoes which runs from the heater core to the water pump stays cold,which is the reason i'm changing the heater core.. The first heater core i purchased with A/C is aluminum and shaped some what different then the brass looking one i took out so i took it back with the old i'm replacing and they ordered the one i needed,well i hope they did but it comes in today so we'll see..

 

One hose into the heater core hot and one cold indicates no flow through the core. The core could be totally blocked but it is unlikely. Although they were replaced, this is a symptom of a bad thermostat or water control valve not opening. The inbound hose should be hot and the outbound should be warm/hot, not cold.

Was the cooling system very dirty? Did the old coolant look milky brown as if it had stop leak added? When you replaced the water control valve could you see if the passage it threads into was blocked?

Do the heat/ac vacuum controls in the car work e.g., air comes out where you place the controls? Defrost on the windshield, heat on the floor etc.?

First, try applying vacuum to the water control valve see if it changes anything, if nothing changes replace the water control valve temporarily with a fitting from a hardware store and run the heater hose directly to the intake and try a different thermostat.

 

Yes the cooling system was very very dirty with stop leak.. So what i did was give it a good flush,that's reason i'm thinking the heater core is stopped up.. Now for the water control valve the water runs through it just fine..

 

If the core may be stopped up, remove both hoses from the engine.
Couple a garden hose with your hands up to each hose at a time and see if you can flush anything out either way. Coupling the hose with your hands will result in some water sprays but will protect the core from overpressuring.
Try that before going through the pains of pulling the core.

 

Good morning guys it's me again.. Well the core has been changed and unlike the old core im getting good coolant flow so just as i expected the old core was stopped up.. Now the down side to all this is i still have no heat.. So next step is the control valve and the thermostat since both are fairly cheap.. For some reason im thinking heat control valve.. But my part stores don't carry the one i need so im going to check ebay.. Seen a few on there for pretty good prices.. I'll keep you all updated..

P.S. Could it be the climate control switch in the inside?? The reason i asked is because when i turn on the defrost my A/C compressor comes on.. Does the compressor suppose to do it when i turn on the defrost??

 

Stop leak ... stop flow .... stop using it ...


Gawd I hate that stuff with a vengeance. Dad used it once on a '70 nova ... 2 days later, blew a hole outta the middle of the rad I could fit my head through. That was back in the day when your entire family could enjoy the ride swinging on the back of the tow truck.

 

I don't use that stuff it causes to many problems.. That's one of the reasons why i'm going through the whole cooling system..

 

Yes, to dehumidify the air. Select your temperature with the temp lever.

 

Is one hose still hot and one cold? Can you explain what is meant by the now "good flow"? If one hose is hot and one is cold it still sounds like a bad thermostat. Have seen quality new ones bad out of the box.

Have seen and hope this is not the case, the back intake passage where the water valve threads in getting quite dirty/blocked. If it is blocked the intake will have to be removed.

There are two systems working together, the coolant/liquid system and the heat a/c air flow ventilation system. Until there is hot coolant in to the core with warm coolant outflowing there will not be heat in the car. Try to achieve heat into the core and warmth out first. After that, if there is still no heat in the car look for cold air getting blended into the hot air making it cold.

About the A/C being on in defrost mode, pretty sure that is normal. A reason not to drive in the defrost mode of course, except when needed.

Hope this helps and keep us posted.

 

Okay thanks for the help.. But what i mean about good flow is that since i've changed the core both hose are hot and even the core but at first before i changed the core only one hose would get hot and the other hose was cold and even the core..But now everything is heating just not to the inside.. So now i'm thinking control valve heat control switch in the inside not working properly or thermostat..

 

If the core and both hoses are hot and the engine is not overheating, you have fixed the coolant/liquid issue. With the hot heater core and still no heat the problem should be air flow/blending related, not the thermostat or water control valve.

Do you feel any resistance or hear any movement of air flow doors/dampers etc. when moving the temperature lever from hot to cold or cold to hot? Can you feel any temperature difference in the car with the new core ? Does moving the temperature lever change the temperature of the air flow at all?

 

Yes i feel resistance and hear movement when moving the temp lever but the temp stays the same,cold !! I'm thinking i'm going to pull the whole dash out as soon as it warms up..

 

See if you can find where the temp control cable attaches to the heater box and the crank arm of the temperature door. Make sure that moving the cable is moving the temp door. Sometimes, you can hear the door moving as you slide the lever back and forth.

 

Thanks Lady72 but i have already checked that by moving the glove box and the doors open and close properly.. But it's obvious something somewhere is not working and if i have to i'll strip this car to the frame to find it..

 

Bear,check your PM please...

 

One other thing to check, is your hose going to the dash controls. I had an 82 where the vac hose, which was purple plastic tubing, had rested itself on the intake and melted, thus sealing itself. Cut out the bad piece, spliced it with vac hose and all was good.