Cooling With AC on
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Car: 86 Z28
Engine: 350 TPI
Transmission: T56
Axle/Gears: 3.42 posi
Cooling With AC on
My car gets hot on the highway with the ac on, it will go up almost to 235, but I manually switch the fans on when I notice it getting hot and it cools down to 180 in about 5 minutes. The air dam is still there, the cooling system has all been replaced in the last few years and the coolant is nice and clean and about a 50/50 mix. I have the dual fan setup from an lt1 car in there which is why it cools down so quickly when they are switched on, this happens when the cruise is set at 70 mph. The only thing I don't have on the car is the air diffuser that goes behind the chin spoiler. My air dam does have a little bend to it, would that cause this?
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Car: 1988 GTA
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Transmission: T5
Axle/Gears: 3.45
Re: Cooling With AC on
Air dam has to be sloped forward (like a cow catcher on a train) in order to scoop the airflow into the rad. If it's bent the wrong way it will sigificantly reduce cooling capability.
The other issue that might cause highway overheating is a clogging of the fins in either the condensor or the rad. Careful on this one, they can seems clean by external inspection, but they can still be dirty once you get a look at them when they are separated.
The other issue that might cause highway overheating is a clogging of the fins in either the condensor or the rad. Careful on this one, they can seems clean by external inspection, but they can still be dirty once you get a look at them when they are separated.
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Car: 86 Z28
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Re: Cooling With AC on
Just put the motor in a couple months ago and the condenser was new then and I had the radiator out and washed it all off. I bet its like you were saying and the air dam is bent too much.
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Car: 91 Camaro RS
Engine: empty bay (for now)
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Axle/Gears: 3.42 stock posi disc
Re: Cooling With AC on
the air dam doesnt actually "scoop" air into the rad. it creates a low pressure area that literally sucks air up into the rad. being slightly bent wont make much of a difference. how do you have the fans wired in? are they run off the computer or a fan switch
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Car: 86 Z28
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Re: Cooling With AC on
I'm learning how to tune the car with help of someone in my local car club, and were gonna set the fans to come on sooner so I will be removing the override switch for a nice clean looking interior.
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Re: Cooling With AC on
if it was originally a 1 fan set up, the ecu doesnt control it at all. is controlled strickly by the fan switch in the head.
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Car: 86 Z28
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Re: Cooling With AC on
single fan. It is controlled by the ecu. Nothing in the head but the gauge sender on the drivers side. Unless someone before me converted it over, which I highly doubt since it looked all stock.
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Car: 91 Camaro RS
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Re: Cooling With AC on
ok, i pulled the wiring diagram. 86 did have a single fan controlled by the ecu
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Re: Cooling With AC on
it only over heats on the the highway with the fans off? fans on the highway shouldnt make a difference to the cooling since the air comming in is moving faster than the fans can blow it.
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Car: 86 Z28
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Re: Cooling With AC on
That is correct, its only when the ac is on and the condenser is throwing hot air on the rad. maybe I need a bigger radiator? It cools fine when the ac is off.
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Re: Cooling With AC on
stock 2 fan setups kick the secondary fan on with the ac. single fan setups should also kick the fan on with the ac. do your fans turn on when you turn on the ac? if not you might wanna wire one of them in to come on with the ac.
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Re: Cooling With AC on
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Re: Cooling With AC on
Someone who knows the ins and outs of the PROM code would be more qualified to answer.
As as guess though, I would imagine the ECM would still shut the fan off regardless of A/C ('87-older). '88+, the same pressure switch that sends the A/C signal ground, also grounds the secondary fan relay. So, even if the primary turned off at 35, the secondary would continue to run (with A/C on). Again, this is just a guess, not fact and I could be quite wrong.
As as guess though, I would imagine the ECM would still shut the fan off regardless of A/C ('87-older). '88+, the same pressure switch that sends the A/C signal ground, also grounds the secondary fan relay. So, even if the primary turned off at 35, the secondary would continue to run (with A/C on). Again, this is just a guess, not fact and I could be quite wrong.
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Car: 86 Z28
Engine: 350 TPI
Transmission: T56
Axle/Gears: 3.42 posi
Re: Cooling With AC on
Someone who knows the ins and outs of the PROM code would be more qualified to answer.
As as guess though, I would imagine the ECM would still shut the fan off regardless of A/C ('87-older). '88+, the same pressure switch that sends the A/C signal ground, also grounds the secondary fan relay. So, even if the primary turned off at 35, the secondary would continue to run (with A/C on). Again, this is just a guess, not fact and I could be quite wrong.
As as guess though, I would imagine the ECM would still shut the fan off regardless of A/C ('87-older). '88+, the same pressure switch that sends the A/C signal ground, also grounds the secondary fan relay. So, even if the primary turned off at 35, the secondary would continue to run (with A/C on). Again, this is just a guess, not fact and I could be quite wrong.
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