I replaced the heater core as the old one was leaking and now that the weather has begun to drop I thought I would drive the 66 more. Well the blower works, and I get air; just not hot air. Anyone have any ideas?

 

You must be low on fluid in your radiator. Park with the front end a little higher that the rear end. Take the rad cap off and run the car until warm and add fluid as needed to top off the radiator

 

warm the car up good and feel of the hoses going to and from the heater core .. both should be equally hot..

 

So the hose from the water pump is hot, but the hose from the intake is luke warm.

 

You may be low on 50/50 mix antifreeze / water as Glenn has said. Or your heater core may be plugged. Then again it could be your thermostat is old and staying open.

 

T stat was a thought too, but I figured it worked before the heater core swap..... but then again it might not have

 

New t-stat, radiator, hoses, and core. The blower does work, just not heat. So could the new core be plugged up already? Mixture is 50/50, or close to it.

 

I don't think the core would be clogged already. Sometimes when replacing a heater core you will get a big air bubble in the system, so your radiator will look full but the system will not actually be full. What size t-stat did you install? Check your radiator fluid level.

 

Does your car have a heater control valve on one of your heater hoses? If not just feel both heater hoses. If one is pretty hot going in, you probably have a temp door problem.

 

I hate to be "that guy" but would mixing up the input/output hoses cause an issue?

 

i think the hoses are of different sizes .. one is like a 3/4 and one 5/8 ths maybe ..unhook the smaller hose and run the engine a minute and see if there is flow ...

 

Not really. Maybe a slight less performance but he would still get some heat. I think the blend door isn't opening.

 

I dont think it's the blend door since only one hose is hot. Air pocket seems most likely culprit. Switching hoses would not be an issue since you're just looking for flow thru the core. With the engine running and rad cap off, you should see flow as the thermostat opens then n none when it closes. The level should be a little lower than the neck of the radiator. What does it do if you rev the engine at idle? Can you get any warm air then?

 

Sounds like air in the heater hose, heater core loop.....
The air in the heat loop must be purged or it won't flow as it 'air locks'.

 

Ok, so I finially got time to try some of the suggestions from above out. I tried forcing water, then air through both lines and nada. So I decided to take it apart and see if something was blocking the hoses. The previous heater core had extra long copper tubes so the heater hoses attached in the engine compartment. Well the new core attached at the base of the heater compartment under the dash. Well the lower hose was crimped by 2 1/2 inches and was not getting any flow. Since it is after midnight and firing the 66 up at this hour will surely wake someone, I am forced to wait till the morning to see if this fixes the issue.

 

Sounds promising

 

And I now have heat! Thanks for all the input and advice!