Chrysler Repair: overheating, chrysler lebaron, 1992 chrysler lebaron

Question
We have a 1992 chrysler lebaron 4door we have changed the thermostat the heater core is bad so I bypased it we have flushed it out the fan works the hoses do not leak and they are still plyable the waterpump seems to be pumping but it still overheats this is on a2.5 4 cyl.what do you think im at a loss  

Answer
Hi Eric,
When you drain and refill the 2.5L 4 cyl engine you have to do it in such a way as to not trap air in the cooling system. I'm not certain what impact having the heater core bypassed has, because that loop might also get air trapped in it, but so long as you keep it bypassed it shouldn't matter. And I would not worry about that if refilling it this way fixes it:
You need to drain off (and cooect for reuse) some of the fluid, so open the drain at the bottom of the radiator but leave the cap on the radiator filler. See if the fluid drains out of the overflow bottle as you start the process which it should if the system is tight. After you have drained off a couple of quarts, shut the drain valve. Then remove the plug on the top of the thermostat housing (8 mm hex wrench) and verify that the fluid has drained out of the housing. Then open the radiator filler cap and replace the coolant that you drained, into the system by the filler, but leave the plug off the thermostat housing until you notice that the coolant has filled to the top edge of the housing plug hole. Then put a little bit of anti-lock or grease on the threads of the plug and put it back in the top of the housing. Continue filling to the neck of the radiator cap, and then fill the overflow bottle to the cold line. Now see if that has solved your problem.
If you haven't filled it in this manner before then there is air trapped in the thermostat housing which causes the thermostat to work irratically. Let me know if it doesn't solve the problem. I assume that you by-passed the heater core by putting the by-pass valve in the open position all the time.
Roland