I have been battling the same problem on my 79 pickup, poor heat, swapped it out with an ebay "HVAC Heater Core OSC 98672 fits 79-83 Toyota Pickup 2.2L-L4" Same thing no improvement.
I cut the top off the old one, and the same thing, no divider, am I to assume that this was an aftermarket heater core? Has anyone opened up an OEM core to prove that it does infact have a divider in it???
I was thinking about slotting the top of the core and then silver soldering in a divider, or do the redneck hack and just hammer/dent in the center enough to force a bit more through the core
whats the worst that could happen? have to replace the defective piece of junk
I am with you though how frustrating it has been messing with this, I have had the core out more times than I want to count. Its going to really piss me off if they are truly just designed incorrectly, by having the divider missing.
