marco93L

I can drive the car all around town slow all the way to 55 mph and it is fine. If I get it over 55mph, it will start to climb pretty fast with the AC on. I can turn the AC off and it drops to normal temps of 200* even if I am doing 80 mph, it doesnt overheat.

I have checked the tranny fluid-ok, antifreeze-ok, air deflector under the car-ok......

What else could it be?

I know the AC is still working great, but can it be heading south without me knowing it.

Also, can the thermostate cause it. I have had them do bad, but it never acted in the manner that this is.

Thanks ahead!!!

LS6427

iTrader: (2)

If it only happens when you turn the A/C on, on the highway, I'd have to guess you have a seriously dirty condensor, on the outside of it.
Make sure nothing is jammed up in front of the condensor too.......

Does it overheat with the A/C "on" when you drive around in the city?

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ivan_key

Could be your fans kicking off

LS6427

iTrader: (2)

Fans should never be on during highway cruising. All cooling is done by the ram air from the lower air dam. Fans are for city driving and stop and go cooling when airflow is insufficent.

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ivan_key

Huh well I didn't know that, I know my lt1 camaro overheated on the highway when I took a fans stopped working so I just wired them up to run all the time

senicalj4579

iTrader: (41)

Yep clean your condensor good. While your at it do your radiator to. Another thing is you dont want your fans running all the time.

ivan_key

Why don't you want them running all the time, none of cars fans are like that now but just wondering

LS6427

iTrader: (2)

You're going to kill the life-span of the fan motors.

But again, if your fans are coming on while cruising on the highway....you have a cooling issue. Mine never ever come on, no matter how hot it is out A/C on full blast.

You need to find out why you aren;'t cooling sufficiently while cruising.

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ivan_key

True. The air dam under the car was broke before, back to op's post, I'm not sure then, I have seen leafs and other junk get stuck Between then condenser and the rad

2000 TAWS6

iTrader: (1)

I found a couple of publix plastic bags wrapped around the fans when I bought the car, made a big difference when I took them out.

I thought when the A/C is on that one fan is automatically on all the time?

OP: You need to get under the car and inspect the front end to be sure nothing is obstructing the air flow. Do both fans work?

Jon

LS6427

iTrader: (2)

Fans only go on when the PCM reads a certain temp.

Also, one fan cannot work alone....they always are either on LOW together...or HIGH together.....or OFF together.

If only one fan is working....then the other fans relay has fried and it will never go on till a new relay is installed.


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O2Form

The fans should come on when the ac is on.......

BLINGOLE

iTrader: (5)

when radiators are clogged they seem to always get hotter the faster you go. I would make sure it flows good and the air path is clean

LS6427

iTrader: (2)

Mine will not come on when I turn my A/C "on".......they only come when commanded to by the PCM when my temps reach a certain temp....which I have no idea what that is, my tuner did it 9 years ago.

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LS6427

iTrader: (2)

The temp of the coolant in the radiator won't effect how the a/c system performs. The outside ambient air goes through the condensor first........

Now a hot condensor because its exterior is dirty will cause the radiator coolant to rise......and cause quick overheating during city driving on a hot day.

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FiredUpZ28

I think you have a problem if the fans don't come on when you command A/C on.

OP has a radiator cooling capacity issue. I also vote obstruction.

LS6427

iTrader: (2)

13 years with my car.......always runs cool as a cucumber.

And you took that quote of mine when I was talking about "while cruising on the highway".........

My fans never come on while cruising.......no matter what. It stays around 180*-185*, even on seriously hot days.

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O2Form

Fans should come on when IF the ac is working properly. The PCM looks at the pressure in the ac system and if its high enough turns on the fans. My 02 runs the fans every time the ac is on and so does my 99.......

senicalj4579

iTrader: (41)

DING DING DING BINGO.
I just installed a bigger ssra on my car yesterday. My high speed fans never tured off when I was city driving. I took that sucker out and put back my smaller ssra. All better now, stays 194f-203f on most summer days with stock t stat and not stock fan settings.
Stock fan is suposed to come on at 185 for ac I believe. But I deleted my ac anyway ha