Need help with heat, children are freezing!

[R_W]

OK so I rebuilt the heater, new core, new hoses, new motor, new fan. Flushed radiator. Coolant is full, new 195 thermostat. hose attachments match diagrams posted. Late 70's 350.

I attempted to burp the heater core by pulling off the outlet hose and letting the truck warm up. When the thermostat started to open, a weak flow came out, then would stop. Then a little more, then would stop. I kind of expected a steady flow...

Anyway, fan works, blows right direction, but always blows cold. Air box flapper works. Inlet hose gets hot, outlet hose never seems to get hot. It is acting like it still has an air lock, but not sure.

3 core radiator, system cools really good, even on hot days in summer.

Is it too cold for my thermostat to open up enough?

And just in case DCS is cruising the website, I do not drive the children around without car seats

[donthekawguy]

Try pulling the core out and filling the inlet with anti freeze then plug the hole with your finger while you warm it up. Sounds like you have a stubborn air pocket.

[awbrown]

you are not getting any flow through the core , post a picture of how your hoses are routed and where they hook up to the engine .. if you have a new core (brand new not used ) then your problem is else where .. both tubes on the heater core should be hot ,if only one is it has to be a flow problem .. you should not have to "burp" the heater core because flow will start the minute you fire the engine ,the line coming from the water pump will have more than enough pressure to flush out any air in the heater core.. 2 more things to think about , do you have a temp gauge on the vehicle??? are you sure your thermostat is working properly???

[awbrown]

Oh do you have the deluxe heater or the one mounted in the truck cab ??? My 63 has the original heater core , the one that has the valve on it (the 4 control as oposed to the 2 control) I had to make sure the valve on the heater core was open , they don't often work properly so you depending on which core you have it is one more thing to check...

[tincan1966]

Originally Posted by awbrown

you are not getting any flow through the core , post a picture of how your hoses are routed and where they hook up to the engine .. if you have a new core (brand new not used ) then your problem is else where .. both tubes on the heater core should be hot ,if only one is it has to be a flow problem .. you should not have to "burp" the heater core because flow will start the minute you fire the engine ,the line coming from the water pump will have more than enough pressure to flush out any air in the heater core.. 2 more things to think about , do you have a temp gauge on the vehicle??? are you sure your thermostat is working properly???

The 5/8" heater hose from the intake manifold near the thermostat is the supply to the heater core, the 3/4" hose to the water pump is the return.

It also depends on which intake manifold gaskets you have installed, and could be installed incorrectly. Later model engines(the center bolt valve cover ones) draw the heater supply from the passenger side REAR corner of the intake manifold and return from the core to the radiator. These engines use a different intake gasket than the older V8's, and have a restrictor installed.

Something you can do is install a "flush T" in the 5/8 hose and fill the core that way, or remove the 5/8 hose from the core, install a short length of hose to the core and fill it that way,with the radiator cap on and tight, then reconnect your hose from the intake to it. It is completely possible to have aire trapped, since the core is about 6" above the radiator neck

[R_W]

Here is the routing, new heater core. There is an interesting port plugged on the manifold that is circled in the photo above...

When I got it there were no heater hoses, both ports I am using were plugged.

[tincan1966]

Your problem is the only water you will get to the core is going to be after thert-stat opens. I would move that hose to the plugged port on the front passenger side of intake, that you have circled. You will have continuous water flow then. That is the supply to the core. You can plug the hole in the top of the t-stat housing.
The other routing looks correct and should work fine.
Hope that helps. Good luck! and thanks for posting pic, it explained your setup well.

[1963c-10]

Originally Posted by tincan1966

Your problem is the only water you will get to the core is going to be after thert-stat opens. I would move that hose to the plugged port on the front passenger side of intake, that you have circled. You will have continuous water flow then. That is the supply to the core. You can plug the hole in the top of the t-stat housing.
The other routing looks correct and should work fine.
Hope that helps. Good luck! and thanks for posting pic, it explained your setup well.

x2....move to the plugged port

[R_W]

Thanks guys, I'll give that a go tomorrow and post results

[1963c-10]

With any luck, the plug that you remove will fit the thermostat housing to plug that port.

[jtrichard]

the old saying goes a picture is worth a thousand words is so true........ the port you have used is for smog crap and you wont get any flow to the heater until the stat opens and then VERY LITTLE as said above move the 5/8 to the plugged port you have in red square and it should roast you out of the cab then you will hear "its to hot" LOL

[RANDY COX]

Yep x3 I know the one in my truck after it warms up it gets so hot It'll burn you best heater I've had in an old truck..

[aerotruk63]

Please post a pic of the kids smiling, after you have heat!

[hotrodder]

yEP, MOVE THE HOSE. THEN THEY WILL BE SMILEING LIKE THE PICTURE

[R_W]

Originally Posted by aerotruk63

Please post a pic of the kids smiling, after you have heat!

ROASTING HOT BABY!!!!

[1963c-10]

haha.....right on. Great pic and glad the heats back on.

[FetchMeAPepsi]

Awesome mini-story with the kids! I subscribed just to see how it turned out. Stay toasty guys!

[awbrown]

Originally Posted by awbrown

you are not getting any flow through the core , post a picture of how your hoses are routed and where they hook up to the engine .. if you have a new core (brand new not used ) then your problem is else where .. both tubes on the heater core should be hot ,if only one is it has to be a flow problem .. you should not have to "burp" the heater core because flow will start the minute you fire the engine ,the line coming from the water pump will have more than enough pressure to flush out any air in the heater core.. 2 more things to think about , do you have a temp gauge on the vehicle??? are you sure your thermostat is working properly???

A picture is worth a few words and about 50 degrees worth of heat .. New heater core 75 bucks , new hoses 20 bucks new thermostat 18 bucks new fan motor 50 bucks , heat in truck and smiling kids , priceless .... I rode to Springfeild Mass. once with a GM tech ,we about froze to death , I looked under the hood to find out his hoses were not routed correctly ,so we fixed it in the parking lot after finding a 7/8 wrench and a pipe nipple at the swap meet we were at ,it was a long trip home for the guy cause I rubbed it in ..

[earl84]

Originally Posted by r_w

roasting hot baby!!!!

best. Followup. Ever!

[TJ's Chevy]

Glad you got yer heater fixed!!!! I'm lucky mine still works!!! All original 48 year old heater!!! And still warms the cab up! lol!

[Jeff La]

Great thread

[joedoh]

I traded a bug for a galaxie once on the coldest night in a long time, -17 wind chills. My wife and daughter agreed to the trip across town in the bug, with its meted allowance of hot air heating (no coolant lines were backwards!), because the galaxie was advertised as having a 390 and a heater that would "melt yer face". After a lukewarm trip out west, we started for home and....

the heat did not work. our breath was freezing on the inside of the windshield, my daughter and the dog huddled in the back seat, and we froze all the way home. The next day I called the guy to chew him out and it turns out if you turned on the dealer installed AC, it would bypass the heater with nice fresh air from outside.

[jtrichard]

T J you do know that now you have said something about how good and old your heater is it will soon start leaking

[NEWFISHER]

Originally Posted by jtrichard

T J you do know that now you have said something about how good and old your heater is it will soon start leaking

Truth

[Rich 5150 69]

GREAT ENDING...!