Help! No heat!

[drock87]

I am trying to survive the Great Freeze, but I have some issues. Namely, I am not getting any heat. I have replaced the thermostat, which was actually ok. The car is heating up (not all the way, but to where I should have heat.) What else should I be looking for? I wasn't sure if this made any difference, but I disconnected the heater valve ball thing (can I just eliminate that? My car's AC will likely never work again, or at least for a long time?) Also, could it just be so cold that it just won't work? When I replaced the thermostat last night, I did it in my shop at work, and I let the car run for a while in the shop with the exhaust vent turned on. The heat started working when I disconnected the vacuum ball thing (which could coincidentally be the car hit warm-up mode) Since my heat works above 10 degrees normally, I am thinking to rule out my heater core. Correct me if I'm wrong. Thanks!

[vangremlin]

When I replaced my heater core a couple weeks ago, I had to burp the core by slightly removing the upper hose to the core and letting some coolant escape.  Until I did that I wasn't getting any heat.  Yesterday I was getting heat within 3 miles even though it was sub-zero temps.  Hopefully that will work for you, its a lot easier than swapping out the core!

[drock87]

When I replaced my heater core a couple weeks ago, I had to burp the core by slightly removing the upper hose to the core and letting some coolant escape.  Until I did that I wasn't getting any heat.  Yesterday I was getting heat within 3 miles even though it was sub-zero temps.  Hopefully that will work for you, its a lot easier than swapping out the core!

Thanks Vangremlin. Maybe I'll try that. Like I said, last night when I had it warming up in the shop, I got heat and was able to keep it driving around. But same thing this morning, no heat and I let it run for 10-15 minutes and drove it a mile.

[IowaEagle]

If you have a flushing tee already installed just have it higher than the rest of the cooling system and then crack the cap open while engine is running.  That tends to get rid of most if not all of the air.

[Monkeyjoe]

I would say air in the system also.  It is not too cold for the heat.  I run mine in Wyoming and have driven in -20 and -30 and always had good heat.  Last year my heat valve started to stick a little so I had to open the hood and touch the linkage and it would open. 

[drock87]

I would say air in the system also.  It is not too cold for the heat.  I run mine in Wyoming and have driven in -20 and -30 and always had good heat.  Last year my heat valve started to stick a little so I had to open the hood and touch the linkage and it would open.

Best way to get the air out?

[vangremlin]

I would say air in the system also.  It is not too cold for the heat.  I run mine in Wyoming and have driven in -20 and -30 and always had good heat.  Last year my heat valve started to stick a little so I had to open the hood and touch the linkage and it would open.

Best way to get the air out?

Here is how I did it, following Jurjen's instructions.  With the car running (but not overly hot), loosen the hose clamp on the 3/4" hose that goes to the upper pipe on the heater core.  Pull the hose off just slightly until there is some coolant that leaks out - the air should come out at the same time.  Push the hose back on and tighten the clamp, and enjoy the warm air in your Eagle.

[captspillane]

Feel the hoses coming into and out of the heater core. They should be hot. If they are not, then you haven't gotten your vacuum disconnect open yet. If it's warm then the valve is partially open only. It should be just as hot as the rest of the hose, which is almost too hot to touch.

If it is fully hot and the air is bled and you still don't feel warm, the next thing to suspect is a broken heater control. The AMC heater control is very often broken or popped apart.

Pull the center of the dash, take the four screws out on the edges of the heater control, and let it sink down so that you can see the top. Make sure all the cables are in place. Several times I've found cables that popped out of place but didn't break, so I just exercised the cable abit and put it back on with good results. Many other times I've found broken levers. There is more than one cable pulled or pushed by the heat control.. In that case I just look at where it should be when in the hot position from the movement of the broken lever and then I just pull the wire out or in to where it belongs and then put it back together until it's time to turn it back off in about June or so.

[vangremlin]

Feel the hoses coming into and out of the heater core. They should be hot. If they are not, then you haven't gotten your vacuum disconnect open yet. If it's warm then the valve is partially open only. It should be just as hot as the rest of the hose, which is almost too hot to touch.

If it is fully hot and the air is bled and you still don't feel warm, the next thing to suspect is a broken heater control. The AMC heater control is very often broken or popped apart.

When I was having my problems, the 5/8" hose from the intake manifold was hot, the 3/4" hose going back to the front of the engine was not.  I don't have A/C so I don't have a valve in my system.

[drock87]

I'm beginning to fully suspect my heater valve; however, I still need to bleed it. I actually had heat going home from work today, so its cooling down.

Capt., I almost don't need to pull my heater controls apart to know what works, and what doesn't. The AC switch works, because the little line going to the heater valve pulls vacuum with it on. The temp adjustment works fine. The three settings: heat, hi-low, and defrost don't do anything. I just get air (hot or cold, but hopefully hot) out of all vents. While I know that needs fixing, basically with the side vents and AC vents closed, that is my favorite setting anyways. Half defrost, half right foot.

Now, I have had a few people tell me on Facebook that I can manually pull the valve if not opened. However, the person who gave me pictures has a different valve than I do. Mine is the Autozone style (plus rust!), see here: http://www.autozone.com/autozone/parts/Everco-Heater-Control-Valve/1985-AMC-Eagle/_/N-ijg8pZ91sh0?itemIdentifier=58301_0_0_

I do not see any manual adjustments whatsoever.

So, my next steps are to bleed the system, then get a new heater valve. If neither fix it (which I may never know because it will be a scorching hot 23 degrees tomorrow), I may just take it to the shop and have them take a gander. I have an excellent HVAC mechanic down the street.

[captspillane]

The top lever puts the air where you want it, which you apparently have right. The bottom lever, however, with the blue to red temperature scale puts a flap over the heater core and prevents air from going through it. That could certainly explain your problem. If those inlet and outlet lines are both hot and the air is still cold, it's the diverter flap in the wrong position.

[Amc1320]

Like the Capt said,  mine the cable had come off the rod on the flap, pretty easy to happen

[drock87]

Update:

Here is what I did. I am not sure if any one of these really fixed my problem single-handedly, but, nonetheless, it is fixed.

1st, I replaced the thermostat. The old one worked, but the new one seems to work a little better. Whatever.

2nd, Whilst doing the thermostat, I might have corrected another problem. When you replace a thermostat, you lose coolant. I replaced lost coolant. But then, idiot me didn't get the top radiator hose back on tight; I started leaking coolant. That being said, I do not think I remotely had the right blend going on, and I think to start my coolant was too watery and not enough antifreeze. Now that I have the hose on right, my antifreeze mix is much more accurate and is properly topped off.

3rd, I "fiddled" with the heater valve. It was NOT opening all the way, which is what I remember the first time this happened last week. Now its open, and I disconnected the vacuum line. My AC does not, nor likely will it ever work; someone tell me if there is a reason this SHOULD be connected.

And....now I have heat. Nice, warm heat. It comes on quickly, and while in Zero degree temps driving the car had trouble maintaining optimum temperature, it did not lose heat. I might drive with cardboard over the grill if this ever happens again.

Thank you everyone for the help!

[IowaEagle]

You may have accidently burped the system too with a loose hose.  You may want to keep the valve for when it is warm or it will get real toasty in your car.

[captspillane]

The valve is still important for you even without AC. Your AC box can't flap off and keep air from going across the heater core like the non AC box has the ability to do. To save space to fit the AC fins in the same box, I'm pretty sure there is no way to keep the air from going across the heater core before going across the AC fins. With or without AC you'll have hot air blasting on you without that bypass.

My Green wagon actually does have crisp, cold R134 AC and it couldn't get the air cold enough to overcome how hot the heater core got it. I was roasting in the summer time until I broke down and stole a valve from a parts car and put it on where I had bypassed it over the winter before.