I changed out the heater core on my 65 289 and I followed the instructions that came with the heater core. It ends up that it showed them switched (top port of heater core to water pump, bottom port to top of the engine). I ran the car about 10 minutes with them backwards and almost all of the radiator fluid shot back out the radiator cap and overflow tube after I shut the car off and released the pressure on my radiator cap. The radiator fluid was not hot at all. I changed them to the correct orientation, but now it seems like the coolant is not circulating and the radiator is full of coolant. The heater is also not getting hot. Could I have messed something up having the hoses switched? Any ideas?

Thanks
Eric
'65 289 Coupe

 

The way they are hooked up makes very little differnce in the performance of the heater or anything else for that matter. What other work did you do? Pressure in the radiator without the engine getting hot is usually a sign of a blown head gasket.

 

The heater hoses can be hooked up any way you want them. Just for grins and a lesson, try bypassing the heater box by putting in an L in the end of the heater hose to connect directly to the other heater hose, therfore bypassing the heater altogether. See if that changes anything. Or, just put in a shut-off valve in the top hose just before it goes into the rad, therefore shutting off all water flow to the heater core.

 

I bled the coolant system because I had a feeling that there was more air than coolant in the system. I then ran the car for about 10 minutes and added more coolant. Everything seems to be working fine now. Could too much air in the system caused the coolant to shoot out the cap?

 

Absolutely. Air in the system needs to be burped so that only fluid is present in the system and not air.

 

Yep...air does that.

I generally run one heater hose off the back of my intake to clean it up a little. Then I installed a 20lb cap, blew the heater core, pulled the heater box, and used that space for my MSD. BTW, anti-freeze + black carpet = [:'(]

 

The only reason for top-bottom orientation at all would be to help purge the heater core of air. Unless it is specificly diagramed as top inlet bottom outlet, or there are molded hoses or pipes that constrain the hookup a certain way, I usually put the inlet (manifold hose) at the bottom and outlet (water pump hose) at the top. Small block Ford engines can be a royal pain to get all the air out of.