NOT COOLING still not cooling,goes down to 28-38 and goes back up,

first check the cooling system ie coolant level. the ecm is shutting down the engine because it thinks its overheating may be just the engine thermostat try that and also check the radiator for blockage airflow ect

Try the usual back flush procedure, change water pump, thermostat and all hoses.

Hello: Check the radiator cooling fan. With engine running and A/C on open hood look down on the back-side of the grill, that's where the cooling fan is. It should be running, if not check the fuses, cooling fan relays/module if they are ok then you may have a cooling fan motor failure. You can use jumper cables to hot wire the fan motor to see if it runs.

Check your cooling fans and cooling system. Drain and flush your system if you have not done so lately. Make sure your radiator is clean.

Hi,

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heatman101

Read your maunual. It might be normal. A 4 degree split in your set back heateing control is about normal. It is that way so you can turn your unit on and never really need to touch it again. When the temp goes up, cooling goes on. When the temp goes down, heating comes on.

Valve cover leak (oil) will not cause this problem, what needs to be checked is your radiator cooling fan, more then likely not working, that's why when your going down the freeway it don't over heat, you have air going through radiator, but when at stop, no air going through radiator to cool coolant before it goes back through engine, starts to get hot, and oil will also thin out, and have low oil pressure, check cooling fan's or fan, for voltage, should have voltage at normal oper. temp. about 210 - 220 deg., if you do have voltage and fan are not on, replace fan motor.

if it only gets a little hotter, then there's nothing to worry about but if the temp goes into the red then you may have to get a radiator flush to remove any thing that shouldnt be there. also check to make sure that your sensor isn't just going out.
~Dan Herzberg~

Check out clarks-garage.com he has a complete troubleshooting guide for your cooling system along with a schematic. In short, check the low speed resistor on the firewall. Should be around one ohm.

Sounds like the thermostat is trying to stick,and is causing the engine to over heat,therefore condenser is not cooling the freon down enough to cool.Have the thermostat changed and the cooling system bled out,this is most likely the cause.