today my car was coming close to overheating,this is what happened i test drove my around the block my ac was turned on when ever im cruising with the ac on the temp will creep up slowly, it got a lil bit below the 3/4 mark,when i got home i turned it off i opened up the hood and i heard boiling and garling from the radiator and overflow tank. After a lil bit i fired it back up without the ac on and the temp went to the middle while low speed fans on. I noticed that whenever i use the AC the temp while im driving will creep up.

Whenever Im not using the AC the temp in my car will be perfect no running hot, no overheating and no boiling from overflow,even when im cruising without AC my temp will stay between 180-190. I have a couple questions to ask, i noticed when i turn on the AC both fans are running at low speed, then after a few seconds it will run at high speed, are the fans supposed to run like that when the AC is turned on? my 2nd question is why when i use my AC my car runs hot and almost overheat. Thank u guys for the help

 

Yes, the low speed fans should come on when you turn on the A/C.

The A/C increases the heat load to the radiator. The condensor is right in front of the radiator. The condensor pulls heat out of the freon to cause it to condense. The hot air coming off the condensor then enters the radiator. A minor cooling problem in the radiator without the A/C on will become a larger problem when the A/C is on, and the air hitting the radiator is warmer.

Did you check the coolant level in the radiator?

 

thank u for answering my thread Fred,before I drove the car the coolant was full to the top of the neck of the radiator.just now I ran the car without the AC on and the cars temp was running perfect,then I tried the AC on and drove the car for a couple of min the temp seemed fine. But then i turned it off opened the hood, and heard boiling/garling from the overflow tank,it sounded like the overflow was sucking water from the radiator b/c i could hear the overflow slurping the coolant/water.

Also the rad cap is new i just bought one from the chevy dealer its the stock one the plastic one it is an 18 psi.
another thing my fans also come at full speed too when the AC is turned on is full speed supposed to come on to when AC is turned on

 

Is the radiator still full after the "gurgling"?

 

the overflow tanks dipstick is showing thats its full its past the hot mark,did u want me to open the radiator cap as soon as it cools off to check the level,i will as soon as it cools off,and ill let u kno Fred. Thank u again

 

hey Fred i just took the radiator cap to check the coolant and the coolant is full. where should i go from here

 

You might try bleeding it. It could have developed an air pocket.

 

I did open the bleeder screws and there are no air pockets,there isnt any spitting coming from the screws and no bubbles. the coolant and water come out clear.and the coolant is full

 

Did this problem start before or after you bought the new radiator cap?

 

this problem didnt start till i started using the A/C during this summer time like the middle of june because thats when my bro and i put the freon in for the AC,i just bought the cap in april like 2 months ago b/c the other one was old,in april i didnt have any issues.i used a pressure tester to test the new rad cap,and it holds pressure,i pressurized the system too and it hold pressure too.

 

Ttt

 

Is your A/C system working correctly?

 

hey Fred, yes it is working im assuming you mean by working correctly by it blowing cold air and yes it is blowing cold air,and the fans are coming on at two different speeds low and high. but now i think i diagnosed the issue i check the radiator cap and there is rust color debri on it. Now by seeing that it needs a flush,but i was actually thinikng it needs a new radiator b/c im 23 now ive had this car since i was 19 and idk if the previous owner had ever taken care of the radiator.

Ive flushed the radiator with radiator flush cleaner and followed the directions as instructed to and when i looked inside of the neck of the radiator with a flashlight the rust is still there all brown and still the same.

So rather waste time and keep on flushing the radiator out I should just buy a new one and start fresh knowing that i feel better knowing i have a great radiator. So my next step is the radiator b/c everything else works in my cooling system but the only thing i can recall that i havent changed is the radiator. When i changed the radiator ill let u kno the results,if anyone else has any info or ideas i appreciate it thank u

 

That would take us back to post #2........

"A minor cooling problem in the radiator without the A/C on will become a larger problem when the A/C is on, and the air hitting the radiator is warmer."

 

hey Fred im sorry i didnt read the post carefully about what you said about if there is a cooling problem in the radiator it will become larger later on with the AC i just came back from the radiator shop with a new radiator,after i install it ill let you guys know the results but i appreciate everything that you guys have done about my problem.

This might sound stupid but id rather learn now then wait till later,now when i bleed the air from the two coolant hoses is it normal for the drivebelt to get wet, b/c i had to change my belt last week b/c the belt noise wouldnt stop and after i installed a new one i didnt hear it anymore,i am using a towel to cover the opti so it doesnt get wet. My car right now has a new belt,and when i bleed the air out i dont want the belt to get wet so what should i do?