I've had the car right at 3 years now.

Last week or the week prior it was a beautiful sunny day, but it was cold. Probably 38 degrees in the morning. I hadn't driven the car in a while, so I really wanted to drive it to work.

Well, I got very little heat, if any, on the 52 mile drive to work. I froze my *** off. It's the first time trying to use the heat since owning the car. I have some questions to try and isolate the problem, if there is, in fact one, so here goes....but first, I want to preface this by saying I have all the records since day 1, and the heater core has apparently never been changed.

Additionally, the car has a Brian Harris chip and a 160 thermostat.

Here goes:

1) With the HVAC controls off, does turning on the fan default the air to the defroster?
2) When i select Heater, and temperature control to hot, i can feel air flow from behind the "pod," but it's not great. (No air from defrost or AC vents.)
3) Both hoses connected to the heater control valve and going to the heater core are/get warm. (The high today was only 37.)
4) (May seem like an odd question.)
If i remove the hard vacuum line that goes to the heater control valve, and place it on my tongue, should I feel vacuum, or is it not that evident/strong?
5) Could the valve on the back of the HVAC control be
the problem?
6) I detest "shotgunning" a problem and changing parts without being definitive, but should I change the heater core?

Next steps?

Thanks!!!

 

Good thing it's not actually cold wherever you are. It's below zero F where I am right now. Hasn't been above freezing for at least a week. Somewhat normal for winter around here. Although, I'm seeing that parts of TX got snow today?
.

1. No. With the controls set to Off, there is no power being fed to anything, including the fan. However, to the extent that air gets rammed into the cowl by the pressure at the base of the windshield at speed, whatever air is forced in accidentally that way, will go to the defrost duct.
2. Not sure where you're going with this.
3. Think of the heater core as like a little radiator. Hot water out of the top of the engine (intake manifold) goes in, air flows over it, cooled water returns to the engine (fitting on WP or on the cold tank of the radiator). If the fan is not running, obviously it won't be giving up much heat, and the cooled water will only be slightly cooled.
4. Under some conditions you should feel vacuum. It should be plenty of suction, basically hard manifold vacuum. Some cars apply vacuum to the valve to open the water flow to the heater core, some to shut it off. I can't remember which way our cars are. I think they're the 2nd kind butt don't take my word for it.
5. Yes. Especially if you hear hissing from it.
6. I'd try flushing it first. Unfortunately the flow from a residential water system isn't always adequate to clear it out fully. Put your hose to the cold water side and blast the crap out of it and see what happens. Butt if it's all built up with scale, or if somebody mixed Dexcool and green juice in the car at some point in its life, you may be out of luck.

 

Sofa, (wish I knew your name....just something inappropriate about calling you "sofa.') LOL! Anyway, mine is Jeff, and I'll be 71 in 10 days. I bought this car first, and I also have a 94 TA vert that is a storage building find from Kansas with 26K miles on it I bought about 2 years ago. A friend of my wife married the old Pontiac/Buick/GMC dealer in Waco, Texas, and we became immediate friends. He found the car. He's 80, and does Mecum and other auctions, and has a pretty large "stable" of cars himself.

I really want a 76 TA like I had when I was 22, (bought it brand new for $6600,) but my wife and I cannot justify the expense, as we're about to retire from her small business, which was not my career.

I live on Lake Whitney, Texas, which is about 50 miles north of Waco, and about 75 miles South of Dallas.

Besides my garage, (which is pretty big,) I bought what used to be an old drive-thru beer barn that I keep toys in. The two TAs swap off between the garage and the barn, depending on which one I want to drive. Right now the 94 is in the garage, along with my wife's Sky Roadster that I bought her for our 35th Anniversary, a Gator, all my tools and equipment, and all her freeze sensitive plants....LOL!!! The 91 is in the barn, along with HER unrestored 71 Cheyenne Shortbed, my boat trailer, and a Seadoo.

We had about a half inch of snow overnight Monday. This morning when I left for work it was 25 degrees, but it's supposed to be 55 this afternoon.

On the way in to work this morning, I stopped at the barn to confirm what I told you.....here goes:

1)------I was totally wrong, so disregard.....The fan does not work with everything selected off.

2)------I'm calling the "pod" the console "extension" that houses the radio and the HVAC controller.
If you compare the fan on high coming out of the defrost vents on the dash, and the air coming out of the floor vents, the air coming out of the floor vents is markedly less. I don't know if anything can be done about it.

3)-----Got it! Understand the concept.

4 and 5)------very little suction in any mode.......but I don't hear any hissing...If I have the HVAC controller set to heat, after the car has warmed up, I can feel that the two hoses going to and from the Heater Control Valve to the heater core are warm, but the heat sucks. Maybe the 160 thermostat. I'm going to email Brian Harris, and ask him if a 180 might make a difference. I think I might pull the controller out, do a good visual, to check the vacuum lines and make sure everything is tight.

6)-----I'm disinclined to try a flush. There's a part of me that says to just change the heater core. Even though prior to my ownership the car spent it's life in Riverside Cali and San Antonio Texas, and heat was probably not used very often, The heater core is no doubt 34 years old, and I can spend the time flushing or changing. I think changing is the better course of action.
(For instance, I bought the 94 knowing the AC compressor was leaking at the assembly mating surfaces. I milked it, and charged it about every 6 months or so, but it got too bad.....so instead of changing just the compressor, I also changed the condenser, evaporator, expansion valve, dryer, and service fittings. Now I get 38 degree air.)

Anyway, any other things in your mind you'd like to share is much appreciated, along with your knowledge. I read your many posts often and appreciate your contributions.

Stay warm!

Jeff