Changed my heater core. Still no heat. Dang

[Mister-B]

Just bought a '69 c20 v8 without AC. The heater core was disconnected, and the hose was looped back. So, I bought a new heater core and hoses. It was really a ***** to install. Had to drop the fender, and of course two of the bolts were rusted on the back side and wouldn't budge, so I had to cut them off. There were a ton of leaves plugged in the firewall and inside the core housing, so I got those out. One thing that was frustrating, is that there's a metal non electrical wire with a loop on the end that goes over a post on top of a door that opens and closes when heater switch in the cab moved right or left. I just don't see how it will stay put. There's nothing to hold it in place.

Anyway, got everything connected and fired up the truck and turned on the heater. Nothing blows out at all. I'm guessing a wire is bad or the blower motor is bad.

Any other ideas?
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[Coley]

Ok, here is a place to start:
Do you still have the water shut off valve mounted in line with the heater hoses in the engine compartment?
Note: this is an apparent metal valve component mounted in line to the left inner fender with a hose running in and a hose running out of it. It is 'actuated' (opened/closed) by a vacuum line.
Its purpose is that when the vehicle is in the a/c mode....the vacuum shuts off the valve thus keeping hot water from entering the heater core and the cab....so more a/c cooling.
Also, make sure if it is in place and the vacuum and heater hose lines are hooked up...and that it is working and allowing water to pass through. After the vehicle warms up check both lines in and out for temperature.
Worth checking to get started.
Good Luck
Coley

[ryans69chevy]

Two things I'd suggest is to test the blower motor making sure it runs. You can do this by having the truck turned off and running a wire from the positive side of the battery to the prong on the blower motor. If this runs make sure you actually have a squirrel cage on the blower motor. If not it's not moving any air. If your blower motor doesn't run replace it. Another thing I'd try if your blower motor runs from the battery but not when it's set up correctly in your truck is to check the heater switch which is located in the cab on top on of metal ducts. It should be right by the glovebox. This is a 4 dollar piece so it wouldn't be a bad idea to replace.

Good luck!
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[SS Tim]

Good try but the truck does not have A/C and its the blower is inop.

First thing to do is do a quick visual check of the orange wire to the blower and see if it looks intact.

At this point you could pull the wire off and jump the blower terminal to the battery positive with a heavy wire.

Or just move inside to the fuse panel and check the fuse with a test light on both ends ignition in run. If you have power there check at the blower motor connector with the switch in all positions. Probably nothing though. If there isn't power at the blower go to the switch and see if there is power going into it via the brown wire. Then check to see if there is power coming out the orange wire with the switch on high. If it is dead then its probably the switch or connector. If it is hot and the light blue and yellow are also hot in the other positions then you need to go to the blower resistor and check it and the connector.

[Mister-B]

Ok guys. Thanks for the help, but I think it resolved itself. This is funny. Took my wife for a drive tonight to get a burger through a drive thru. It's a cold night, but on the ride home, we commented on how it's pretty warm inside the truck, and the windows weren't fogged up. A lightbulb went off in my head, and I decided to feel the floor vent, and it was hot! I adjusted the vent switches, and it blew even harder. Tried the defroster, and it works like a champ! I don't know why it works now. Could be that the truck just needs to be warmed up and moving for it to work properly. I figured I would have at least heard the fan kick on before, even if it would have blown out cold air, since the truck wasn't warmed up, but whatever. I'm not complaining. This is awesome. I love this truck even more now.
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[Andy4639]

What degree water thermastate does it have in it? Make sure you get all the air out of the system also. That could have been the problem in itself the system had air in it. Driving it for a period of time forced it out.
Do you have a over flow on it, if not I recommend you get one for it.

[Mister-B]

Originally Posted by Andy4639

What degree water thermastate does it have in it? Make sure you get all the air out of the system also. That could have been the problem in itself the system had air in it. Driving it for a period of time forced it out.
Do you have a over flow on it, if not I recommend you get one for it.

I don't know what degree thermostat. How do I check that?

I did drain and fill the radiator with fresh fluid since I made my first post, and right before the drive I took. Maybe that made a difference.

It doesn't have an overflow. Guess Ill get one. Why do you recommend one?
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[bk2life]

it'd be cheap insurance to put a new thermostat in it, this will also help heat the engine up to op temp faster and thus heat sooner.

but other than that sounds like your good to go.

mayeb the switch contacts are dirty and withyou playing around with it caused it to work again..

[Mister-B]

Originally Posted by bk2life

it'd be cheap insurance to put a new thermostat in it, this will also help heat the engine up to op temp faster and thus heat sooner.

but other than that sounds like your good to go.

mayeb the switch contacts are dirty and withyou playing around with it caused it to work again..

Good idea. I like cheap insurance. Been doing all sorts of stuff like that. Is the thermostat pretty easy to change? Will I lose any radiator fluid? I just barely drained and filled it. Don't want to do it again for a while
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[Andy4639]

If you follow the top hose from the radiator to motor it's inside that housing. The only way to findout what size it is is to open it up. U will loose some water but not much. It will be written on the thermastate. You can check it by placing it in some hot water on a stove and seeing when it opens. Should be around a 180 degree I would think.
Everytime you drive the truck and it gets to operating temperature and u shut it off it will run water out on the ground by the over flow tube which in time will cause your radator to be low on coolant. If you have a over flow tank on it it will suck the coolant back into the radator when it cools off.

[mrein3]

EVERY time you service the coolant system on any vehicle, make sure you "burp" it when you're done. You can get an air bubble in there that won't allow for proper cab heating/engine cooling.

To burp it you get all your work done then start the vehicle with the radiator cap off and a catch pan under the side of the radiator with the cap.

Fill the radiator to about three fourths of the way from the top.

Start the truck/car.

Let the vehicle warm up until you see coolant flowing through the radiator. When you see this flow the thermostat is opened which after a few minutes will purge the air, burp, the system.

Of course the first time it opens it lets the cold water in from the radiator and will close again so you need to wait until you see a continuous flow through the radiator.

Top the system off and replace the cap.

And like Andy4639 said, the pee tube on this vintage of vehicle is kind of a drag. I installed a recovery tank on my truck. If you don't you need to add some 50/50 coolant/water every now and again.

[dan42]

It also could have been a ground that when you were driving jiggled enough to be work. If it stops working that's where I would start.
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[Coley]

Originally Posted by SS Tim

Good try but the truck does not have A/C and its the blower is inop.

....geez, I've got to get glasses.
I completely read that as the truck having a/c....well, apologies guys and I'm glad it worked out overall.
Coley

[SS Tim]

Been there more often than I care to admit. Trying to help is what makes this work.