2003 sunfire 2.2 ecotec engine, fans working, hoses building pressure replaced thermostat but still over heating

SOURCE: 1999 pontiac sunfire over heats vents blowing cold air

Take the inlet & outlet hose off of the lines feeding your heater coil, where it come off the motor. Do you have good pressure on your water supply to your house????? If Yes. Flush the water thru the heater hose backwards from the diterction that the water normly flows from your car motor. Alot ot the time your heater core will just be plugged up and need to be backflushed. Also make sure that you do not have trash/ leaves in your heater box?????
You can also later on after flushing the H-core out, you can flush your motor, radiator & heater coil by dropping everything out and add water plus 1-can of old style Comett. This is very abrassive!!!! Run the motor for about 1-hour. Then drop all of it out. Put just water back into the system and run again about 10-minutes.Do this flushing about 3-times. You will see how clean your radiator will be, plus the cooler your motor will run.

SOURCE: does my 2003 pontiac sunfire ecotec motor have a

there is still more to check. like the mass air flow sensor, the whole fuel line cleanout, and if its an auto it does have a camshaft sensor. its located into the transmission.

SOURCE: heater wasnt working in 2003 sunfire so just

does blower work,,,try & find heater hoses.see is both are hot,,if not heater core

SOURCE: 1996 sunfire overheating replaced thermostat,

Does the top rubber engine to radiator hoes get hot? If yes then the new thermostat is working. Does the bottom return hose from the radiator back to the engine also get hot? If yes then the pump is OK. If not then there is a blockage in the system and this will need to be flushed out from both the radiator and the engine block using a high pressure hose. Does the radiator fan come on promptly. It should start before the bottom return hose becomes hot. If not then the temperature sensor (different from the temperature sender to the dash display) maybe at fault. Your relay maybe fine but it is the sensor that actually triggers the fan to come on. It may be just bad connection so try wiggling the wires to it when the engine has got warm. The temperature sensor is also important to let the engine computer management system (ECU)know that the engine has reached operating temperature. A failed sensor not only allows overheating but means that the ECU thinks the engine is still cold and runs the engine on a rich mix. Have you noticed lumpy idling when hot and excessive fuel consumption recently? these are symptomatic of a failing sensor.

ZJ Limited

• 17989 Answers
• Posted on Jun 07, 2011

SOURCE: i need a belt diagram

Fig. Serpentine drive belt routing with A/C - 2.2L engine (click image for zoom)

Fig. Serpentine drive belt routing without A/C - 2.2L engine (click image for zoom)

Hope this helps.