Air coming out is always hot even on cold setting and coolant senser keeps going bad

Turn off the AC, that will keep the fans on

Did check for any codes? go to auto zone it is free.

Lack of prestone

engine running too hot.check coolant level, should be 50/50 antifreeze and water.replace thermostat and radiator pressure cap.check antifreeze level in the radiator,coolant level should be just below radiator cap, add coolant to overflow jug,should alway be at the full cold mark.empty coolant overflow jug will allow air be drawed in the coolant system causing overheating.if overheating happens when coming to a long stop.could have faulty engine coolant temperature sensor or bad coolant fan fuse or relay.

Sure the engine coolant will be warmer than the outside temperture and if the car has been sitting a long time in cold weather and the outside temperture warms up it could be the other way around. The coolant temperture sensers aren't real accurate as they are a relaitive senser beween hot and cold and the numbers reported don't have to be real just the change from hot to cold and the reching of the coolant to the operating temperture. Noe it the senser doesn't read the opertating temperture coprrectly you'll have all kinds of problems. The therostaste will try to set the temperture of the water to it's set temperture and can open or close completly to get 195 degrees F. Many times if it's too cold then the stat is bad and needs to be replaced This shows up in alot of cars first thing after winter and the first onset of cold weather when the daily tempertures vary the most from day to night.

Coolant temperture senser can be unplugged or bad. Coolant can be too low to touch senser. Coolant can be too much water and is'nt circulating as it's frozen and where the senser is it is still cold. The senser is in the left rear of the engine facing the firewall it has a two wire weathertight connector unplug the senser and with a papaer clip ground the wire and look to see the gauge go all the way if it does the gauge and wire are good and the senser or the water getting to it is'nt hot.

When you said you replaced all the cooling system parts, you mean the raditor, the hoses, the water pump,the therostate, the raditor fan and it's relays and sensers. If you've done all of this and you correctly purged all the air out of the system then The engine can be making too much heat another way. The coolant temperture senser can say that the engine is cooler than it really is ( makes a rich mixture, to warm the engine) The therostate may be installed unside down or is open all the time or is missing. ( the therostate needs to make the car get up to 200degrees F or the raditior may not get hot enough to remove enough haet to cool the engine. ( hot is good too hot or too cold is bad). Let's say all the cooling system work is good and you did'nt mix more than one kind of antifrezze ( they jel up and not cool.) The exhaust can be stopped up ( causes low performance too) Take out the oxagen senser and connect a pressure gauge ( leave the snser plugged in and grounded) If the pressure goes any higher than 5 Lbs. reving it or anytime then you looking for a clog. A good system revved up and heald staedy should show a vacume. The timing can be wrong ( low performance too) The timing chain can skip time and the measureed compression will be lower that 150 LBS. With the chain skipped the ingtion timing will be slow and that will cause overheating all by it'self. The engine may need an oil change, Gas in the oil from short trips and running too cold sometime. Overheating will rurine the mototr oil and it being bad will make the engine heat. The engine turning hard ( turning the engine by hand you should feel 3 compression shrocks per turn and it should turn easy except as it pressureizes each cyclinder, ( they should all feel the same) the oil should look clear and black, not brown. If it's some other color, coolant may be getting in the oil, The exhaust should'nt smell sweet ( antifreeze leaking into the combustion ) with the car running and the cooling system full with the cap off it shouldn't bubble or steam come out ( it tells their is a leak in the engine to the coolant and it'll blow bubbles in the coolant and the hot exhaust will heat the coolant more than the raditor will remove. It certainly should'nt bubble at all started cold and full.

theres alot of 2002 chevys of different kinds but they all can get a vacume leak the 3.1 and 3.4 even the 4.3 and the 5.7 blow intake gaskets. un plug the pcv valve and the vent hose from the valve cover to the air cleaner hose. plug the holes good with tape and rags till sealed if it runs smooth ar idle then the intake is leaking. Coming into cold weather I did then as fast as I could as there was always another one in the parking lot. Leak coolant too. about half and half, some both. a few were driven too far they were blown. Plug wires and injectores dropping out will do it too. but check engine light on with codes P0300 or any code P0301-308. Vacume leak can set all kinds of stuff from map senser, cam senser Egr back pressure, ramdom cylinder miss to certain cylinder miss. and the leak will be the problem not the sensers or wires

The check engine light should be on with the engine running. The coolant temperture senser may be open at some temps the fastest way to test this is to change the senser ( it's cheap and a high failure rate part all auto parts stores will haveplenty of this high failure part in stock and they fail many ways. If the car ever overheated it's damaged or truly bad. A very good one will optimize fuel mileage so if it's suspect change it anyway as money well spent a working but wrong senser can cost alot of gas on any fuel injection car or truck, You get what you pay for in temp sensers and the brand name ones are better. All of them are suspect to be bad even when new and ohm test at temperture charts are is repair manuels. Crank sensers and cam sensers also get hot and quit they cost more are harder to change and fail more on the 3.8 motor than the 3.1 or the 3.4. Igiton modules do this too but it sounds like its been doing this awhile and modules and crank sensers don't stay half bad very long. they stop altogrther. Temp sensers can stay bad and work wrong. If you can get a scanner hooks to the car on data stream the senser may show room temp when cold but as it heats up goes up then to -34 thats open the system doesn't know that to do as the air charge temp senser doesn't agree and the system fails to start and will check as flooded. Flooring the gas and hoding it there may start it anyway. The trottle position senser were to show open thats the clear flood mode and the injectors won't fire. Tps voltage should show .5 volt les than 1 volt at idel (it'll start) and 5 volts at full throttle or nearly. if it shows with a scanner of a voltmeter on the center wire 5 volts or 0 it won't start. Coolant senser fails more often and is cheaper

Check the water contol valve operation ( under hood connected to heater hoses), do you have a full load of coolant?, also air mix door under dash, is the temp of the coolant hot?.Check them all out, you'll find it