95-del-sol

hey thanks for taking the time to read this I've just recently noticed my heater doesn't work in my car. I will be spending saturday trying to find the problem. the heater and AC blow cold, there is no noticiable difference in temp between hot and cold, with it being fall/winter it's hard to tell if the ac even works.. anyways back to my problems.. how can i diagnose the heater? heater valves, blenddoor, heater core etc..
recent repairs on vehicle include: head gasket repair, dizzy, plugs/wires, radiator/fan.
i bought a cheap ebay rad. and it was "performance" i only bought it because it was cheaper than O.E. and the MIL is on for a failed O2 sensor, i think i damaged it doing the repairs and i've neglected to get that replaced, now i know that the failed 02 would cause the ECU to think it's cold and may not open the heater valve, but my other thought is possibly the radiator if it doesn't actually meet OEM specs that it isn't allowing the engine to warm up..which wouldn't make sense seeing as how i can drive for 3 hours and the heater still blow cold.
while typing this i had JUST remembered i have my rad. fan wires jumped, causing another issue with the engine not getting warmed up when it should, so my new thought is i need a new fan switch (original failed so i jumped the wires) i am going to get the new O2 and switch hopefully soon. and maybe that'll fix my cars issues? BUT IF that's not 100% the issue i have, how could i diag the heater?

joey1320

Wow you need to learn about cooling systems some more...

Is this for a DelSol(your title)? If so, check to see if the heater core valve is opening/moving when you go from cold to hot. It should be(if I remember correctly) by the passenger side firewall area where the thw two heater core hoses go. Sometimes the cable snaps.

If that's working, disconnect the heater core lines and run some water through them. You should have water going into one and out the other. If you do, then your heater core should be fine. If you don't, you prob have a plugged core.

If the hoses/core is good, check to see if your flap motor is activating. There should be a couple of levers and such on the side of heater box(can't recall which side). If you choose different vent positions, those should move.

An aftermarket radiator will not cause your heat to not work. The thermostat opens up at a specific temperature, so the engine should always be pumping out the right temp coolant.

Good luck!