my car overheats when using a/c :( driving without a/c is fine but after driving a few minutes with it on the coolant starts bubbling and slowly the temp stars rising.. im running a brand new visteon aluminum radiator with the 14 inch spal fan that it comes with and another 10 inch spal fan that i welded on, both fans work and cut on at neccasary times, and my thermostat is working fine, even took it out to test if that was the problem and it still over heats..I have also done a compression check and i get 145-150 across the board and no signs of it being the headgasket, any help is appreciated because this south florida heat is killing me

The only other things that I can think of would be the upper coolant hose going to the radiator from the thermostat housing. It tends to get heatsoaked due to it being so close to the ex. manifold and turbo(which in your sig it says your car is turbo). You can also try Redline Water Wetter which you can get at most parts stores. You can mix it with just water or with 50/50 and water, etc. I used it in near 100+ degree weather here in south mississippi during the summer in constant stop and go traffic and occasional street races , and it kept my temps down low enough to where i didn't have to worry about overheating, and thats with a stock radiator, fans,thermostat and hoses on a turbo 420a boosting over 10psi. Import Tuner did a test on Water Wetter a few months back and they got upwards of a 12 degree drop in coolant temps on a n/a car. Good luck and keep us informed.

Shouldn't compression be 180-200?

EDIT: I'm a retard who can't read your sig.

I dont think compression should be an issue really if he is over heating from the A/C fan turning on. I previously had an overheating issue where my main fan wasnt turning on and I would turn the ac fan on and it would cool the engine. (Temp Sensor in my case).

The only other thing I can think of is maybe the radiator/fans cannot provide enough cooling for the radiator fluid.

well its low compression pistions so i think im looking good there, ill try the wetter thing u said to mix in with 50/50. the radiator is brand new aluminum and 2 spal fans that both cut on and work properly, that should be enough to keep the coolant cool. ill also try driving with out my bumper on for a day, too see if im not getting enough airflow due to the front mount

Could be your wiring on your spal fans.

Make sure your fans are turning on at 180 degrees and not shutting off at 200. If you had an auto trans wiring issues with aftermarket fans are common.

minor thing that may not make a hell of a difference, but make sure your coolers are clean, and not clogged with dirt restricting air flow. If your condenser is packed, when it heats up from runnin a/c that just kinda soaks into the radiator.

its manual transmission, and fans dont shut off untill temperture drops, ill check the wiring again but i doubt it...ill go ahead and check the pressure on the condensor maybe it is clogged??? anything i can use to clean it out real good?

A power washer, foaming coil cleaner works well, a garden hose, whatever.

so i cleaned the condensor out with a high powered hose and its still overheating! im going to try the wetter thing mentioned above but if that fails im out of ideas...im thinking about adding another puller fan in front of the condensor

Coolant flowing properly? Never really heard of a water pump getting weak (it just breaks) but air pockets will do it also... do a coolant test also to make sure you don't have a crack maybe in one of your exhaust ports or something that's seeping exhaust gas. Other than that I'm kinda stumped, unless your sensor is bad. mine did about identical but it was the radiator, but you said you have a brand new one, so i ruled that out right off the bat.

If your coolant hoses are good to go along with the bottom ones (not stretched or cracking) then you could always check the radiator cap to make sure its holding pressure. I also vote fan/wiring problem. Are the fans getting enough power to suck air in through the radiator? When you feel the radiator, is the bottom cooler then the top? If so there could be a restriction problem with it. Before you bought the visteon radiator did you have this problem on the stocker? If not then it’s the radiator or the fans not staying on long enough. I don’t think it would be the thermostat to as it would overheat with/without the ac – if all else fails change it (to a 160). Make sure you soldered your connections, to keep them from coming loose while driving. When you put your hand in front of the radiator do you feel the fans sucking air in through the grills? Make sure the CTS is in ohmage specs.

Fall is here...

any updates on this one?

Cant figure it out.. car runs nice and cool under normal driving, everything seems to be working, fans stay on constantly untill it is cool, and the a/c sucks...the pressure on the condensor stars rising with the a/c on, i flushed the system and put fresh coolant with the redline to no avail. im going to try to get a third fan in front of the condensor and see if it'll do the trick...but besides that i dont know what else to do

intresting observation...it was raining yesterday to the point where i couldnt keep my windows open because i was getting soaked, so I decided to turn the a/c on cuz the heat was staring to get to me (and the windows)..after a bit of driving the rain stoped and of course my temp. was going up so i get to the train tracks... after sitting there for a while for the train to pass thru, i thought it would be a good idea to turn on the heat to cool the engine down, but when i did cool air was coming out!! instead of hot...tempt. kept rising until i finally got the car moving and on the highway where hot air finally started coming out, and the temp. started dropping... what does this mean!?!? sitting at idle after the a/c was on, no hot air was coming out and temp.kept getting hotter, but once the car started moving hot air started flowing and temps dropped?

low coolant my friend...when my heater hose was leaking my car did the same thing

I knew it was time to fill my car back up with coolant due to the fact that cold air blew out when I had it set for hot air

My lower radiator hose has a slight slight leak in it currently and I have to re-fill the coolant once maybe every 3 months or so.

Check your coolant level regularly and go over all your hoses thoroughly. If everything seems in check then idk what it could be