I replaced heater control valve with manual valve,blew heater core out with air and also flushed with water.Water is clean coming out heater core both hose are hot.Fan is blowing,heater control lever is moving door on heater control box under dash.I installed 195 degree thermostat heater still no heat I think heater coer must be bad.i need help replacing heater core or solving problem

 

Is the temperature door actually moving? Slight possibility of sheet metal door coming off bell crank inside heater box. Not sure if some small part could be removed to allow some view inside...

If for sure it is moving, the core tubes might be plugged and core needs replacing.
Hopefully someone has some guidance on core replacement for this model. Often the CSM is vague on this topic.

BTW, welcome to the site!

 

Changing the heater core will take you 4-5 hrs . Did you get all the air locks out of the system? Did the thermostat open? Did you check the vacuum module under the dash to see if you have vacuum..... opening the heater doors? Is the manual valve defective ? Pull the glove box door and glove box out and see if you hear the vent doors open when changing heat controls. If you blew the core out with air should be fine other than a possible leak, this wouldn't prevent heat blowing out . If all is good Then we will move on to getting your heater core out.
Good luck Hope this helps,


Eric

 

Hi, welcome to the forum! Please post some pics of your car and tell us a little about yourself and your ride(s).

I'm not sure about a manual heater valve so that's a first for me but it's likely something very simple like a vacuum line that's popped off or something. Has any other work been done on the car, whether under the hood and/or under the dash? Here are a couple of things I'm thinking:

1) Is the temp slider actually connected to the heater box under the dash (behind the glove box)? The is a cable that connects the slider control to the heater unit. If you feel very little resistance when sliding the slider left to right and back, it's possible it is disconnected at either end.

2) Make sure all of the little vacuum lines on the unit under the dash (again, behind the glove box) are connected.

3) Check the vacuum "ball" (sorry I can't think of the technical name for it so it's a ball right now!) on the passenger's side fender well and make sure the little vacuum lines are connected. They pop out pretty easily and then bam, you have no heat or vent controls.

4) Make sure the vacuum line is connected to the heater control valve, including the line that connects directly to the intake manifold.

5) When did the heat work last? What was done since then?

I have 2 '76 98's and have never had a problem like this other than possibly knocking off a line like I mentioned above. 2 seconds later, back to normal. I would also recommend putting a stock heater control valve back in. The heater core being bad wouldn't cause no heat unless it was leaking and you'd know if it was because it would leak right into the car and it would stink like crazy.

We'll help you figure it out. If you decide to replace the heater core (never a bad idea if it's really old), we'll get you through that too. I've done it a number of times on my 98's, which are the same as your 88.

John

 

Awesome post 76 regency... that will help him out I have changed a few myself, also in my 76 with console that wasn't fun at all.

 

Thanks Eric,

I've had both of my cars a VERY long time and there's really nothing I haven't done on them. My black one (in the icon) is a nut and bolt, frame-off restoration so I've literally torn that car completely down to the rails and built it back up again.

I'm sure we'll get his heat working again.

 

And it shows , beautiful car John

 

Does the engine reach full temperature?

Does at least one of the heater hoses get hot and the other one warm? The supply hose should be hot and the return hose should be warm as it exchanges heat out of the core.

Trying to determine if it is coolant temperature and/or a control/air flow problem. Let us know.

 

Just read that you said the hoses are hot...did not catch it until the third read, sorry. If both hoses are hot and there is no temperature loss through the core it does sound like a clogged core.

 

Thank you very much!

 

Thank for y'all help I haven't had time to troubleshoot I will post pictures and introduce my self soon thanks for the help and warm welcome

 

Update I do have heat i didnt replace heater core,the heater only works when selector is on AC and temperature lever is set for the warmest temp.The air is extremely hot when i slide
the temp lever to coldest temp the heat goes away.AC is low on freon and keep blowing thermal protection relay.Compressor runs if i jump it.Puzzled thanks once again for all yall help

 

Good to hear you have heat, Have a look in behind your glove compartment, you will see the cable that runs to top of your heater box, their is a push on washer that holds the cable down on the pin, It could be a possibility that the pin has bent or the cable needs to be retightened. the screw that holds the cable in place is just threaded into the plastic heater box. May need to be retaped to 5/16 if it has pulled out. Hope this helps
Eric

 

John (76 Regency) knows these cars inside out I'm sure he will chime in on this as well, My only experience is with my 76 olds as I have installed the heater core with A/C last summer.

 

MoveSomething, we still don't have much information on your car.

Right now we know it's a '75 Delta with A/C.

Does it have Comfrortron or manual A/C?

How long have you had the car?

Has the heat worked in the past? Do you know when it stopped working?

How many people have messed with the car, and how much, over how long?

First thing I'd say is that it sounds like a vacuum problem, and first thing I'd recommend is to look at the troubleshooting guide in the Chassis Service Manual, which should be able to take you through it step by step.

If you don't have a Chassis Service Manual, Here's one on eBay for $12 with free shipping.
You can also download a digital copy (never quite as good quality) from WildAboutCars.

- Eric

 

Lol sorry not lol at any one....Just the vac lines.....oh boy they dry out and crack.....Fun we all banged our heads on that metal frame work.....lol

 

will do thanks

 

Does your blower motor work in any of the switch speed selections or only when the A/C is on "MAX" ?

 

Yes it works on all speeds

 

OK so the limiter blowing combined with low freon tells me you should recharge your A/C

As for the heat, you said the blower works on all speeds which is good. Does the selector actually work correctly as far as Vent, Heater, Defrost, etc? Does the air blow out of the correct location based on what you've selected?

Also, you said you have heat when it's on A/C and the temp slider is to HOT, what happens when it's not on A/C? Does it just turn off completely, go cold, etc??

Also, please answer Eric's questions above. That will help us all figure this out.

John

 

I don't no if it's an comfrorton or not it has temperature # on the temperature lever that goes from heat to cold.I have had the car for 2years as for as my knowledge goes I'm the only 1 that has messed wit the car since I had it.I did purchase the service manual.i suspect it also may be vacuum leak I do hear a vacuum leak around the AC control unit.

 

If the temperature control has temperature numbers on it, and says "Comfortron" across the face, then you've got Comfortron, and you've just entered a whole other universe of troubleshooting. Easier to carry a cooler full of ice to put down your back when you're hot than it is to fix it.

Either way, a vacuum line hiss from the controller is kind of a giveaway that you've probably got a disabling vacuum leak.
The manual control heads can be carefully disassembled and cleaned.
The Comfortron heads... well...

Still waiting for answers to some questions...

- Eric

 

If you have the #'s going across, you have the optional Tempmatic system. I attached a picture of my '76 Tempmatic for a visual for you.

Like Eric said, if you're hearing a hissing at the controls, you have a vaccum leak for sure. The second pic I attached is of the back of the controls. The circular connector is where the vaccum lines connect. They should be held on with 2 retainers on the ends. If the dash was ever apart, it's possible these were left off and the connector may be loose or have come off entirely.....I suppose it's also possible that maybe one or two lines have come loose and not the whole connector. You'd have to get in there to tell.

I can help walk you through removing the lower dash to get in there to check and fix it if necessary.

We'll help you get it right again.

John

 

Did they switch the name from Comfortron to Tempmatic in 1974 or 1975?

I know '73 was still Comfortron.

- Eric

 

I'm pretty sure it changed in '74 when they changed the dash setup. Although the '74 is a little different than the '75/'76, they are mostly the same.

 

Did they switch the name from Comfortron to Tempmatic in 1974 or 1975?


Although the '74 is a little different than the '75/'76, they are mostly the same


I know at times I see Tempermatic in my 76 when my wife is with me, I'm going to looksie if I can get a comfortron sticker for that side!!

 

I had to read that a few times before I picked up on it....very clever LOL.

Funny how I've seen the same in our (non-Oldsmobile) daily drivers too

 

Any progress on this yet? A much easier way to check/fix the connections just dawned on me. You can actually pull the slider unit out from the front without taking the lower dash out. You just need to remove the "woodgrain" faceplate and then there are 3 5/16" screws holding the slider unit in place. You SHOULD be able to pull it forward enough to check and reconnect any loose lines. If not, you'll have to go back to removing the lower dash.

 

Ok I haven't had time to work on car due to work schedule thanks for info I will update y'all as soon as I work on vehicle again