buddys 99 chevy malibu keeps overheating, help!?

[Mick in AZ]

new water pump and thermostat still overheating, fans are working, heater core is good, water seems to be flowing, the overflow above the thermostat housing is pushing water out. my only thought is the thermostat we put in is bad, any other ideas?

 

[shane w]

bad therm. or u put it in upside down

 

[justin n]

replace rad cap and make shure were it sit is flat