Thread: heater core

I am having issues with my b13 since swapping in a new engine..The heat does not even get warm.
No overheating,new water pump,thermostat and I have bled the cooling system a couple times with no improvement.

I have discovered that the upper heater hose is not getting any coolant and is not even slightly warm.It feels empty.
So I took both hoses off and it is empty,barely anything came out.
I can hook a garden hose to the upper nipple on the firewall and it flows freely and clear out the bottom nipple,but if I connect the water to the lower hose,it wont flow out the top nipple.
Is this normal,or is there a clog or valve I may be unaware of.
I can also blow(with my mouth) through the upper hose that was removed and it will push coolant through the lines on the back of the engine,and out the lower hose off the engine,so i know that flows properly.
Just trying to make sure that the heater core is the problem before tackling that undesireable job of replacing it.

If you've got flow everywhere else in the system then it sounds like the core is the culprit. If you wanted to be sure, you could bypass the heater core and loop the feed and return lines together and see if there's another blockage elsewhere in the system. Sounds to me like the core though...

Make sure your heat selection is selected all the way, that might be causing your blockage issue

Well WTF...I just reversed the hoses and got it to flow the other way...maybe I pushed a clog out and its gonna be ok now that its flowing both ways.
I guess I will put it all back together,refill,rebleed it and give the heat a try....damn man.I hate stuff like this

Might wanna do a flush if it was a clog... I know I know

refilled,bled,and I have heat now!!
That was really weird.
I am gonna have to drive it for a few days and bleed it again just to make sure.
I wasnt able to jack the front up where I was working on it,like I usually do

internal corrosion in the core?