Toyota Camry 1997 causes headache and bitter taste on my tongue. Pls Help!

Hi all:

Update: Yesterday, I put 2 bottles of Bar's Leak stop leak (sealant) into the cooling system (three times the recommended dose ). Result: the odor in cabin (passenger compartment) persists while driving and the same odor is still strong in the engine compartment, especially near the upper radiator hose.

My diagnosis and theory: my heater core is OK. But the flow of coolant may be more obstructed than normal causing the coolant to be overheated (more than 100C). This in turn results in antifreeze penetrating through side wall of the upper radiator hose causing the antifreeze smell in the engine compartment. This odor ends up in the cabin while driving (i.e., penetrating through the firewall). Note: This all happens to my car while the bottom part of the radiator and the lower radiator hose are still cold, even further making me believe that my coolant obstruction theory is correct.

Next approach: remove the thermostat and let the coolant flow freely from start.

Note: because I have put in a new radiator and have flushed the cooling system so many times, I think the coolant flow obstruction comes from either the possibly defective thermostat or a weak water pump (the previous owner just put in a new water pump and I suspect that this new water pump may be weak/defective and started the odor problem causing him to sell the otherwise good car to me). However, dealing with thermostat is much easier and much cheaper, so I will test my theory with the thermostat first.

I will let you know how things turn out.

Madison18