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Ponderings on Radiator Air Flow Through the AC Condenser

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Old Aug 25, 2020 | 05:18 PM
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Tootie Pang's Avatar
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From: Los Angeles
Car: 1989 IROC Convertible
Engine: 350 TPI L98
Transmission: WC T5
Axle/Gears: 3.42
Ponderings on Radiator Air Flow Through the AC Condenser

On cars with AC, is all or most of the radiator inlet air supposed to be pulled through the condenser? The condenser seems much more restrictive than my radiator yet the all the fresh air from the underside and front of the car is brought up in front of the condenser by the plastic panels down there. In fact, the edges of the radiator and condenser are sealed and the bottom is the support so air can only bypass the condenser by going up and passed the face of it, over the top of it, then down into the space between the radiator and the condenser- only about 1" gap all the way over and in between. This does not seem like a good design.

In fact, when I turn on my AC, the temperature of the car rises by about 30-40 degrees, but the AC works great.

I am wondering if I am somehow missing a condenser bypass path or if, in fact, the radiator is designed to breath mostly through the condenser.

Maybe I could kick the bottom of the condenser towards the front of the car (slant it) so that the radiator taps directly into the upflow from the fresh air duct panels bringing air in?
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Old Aug 25, 2020 | 06:22 PM
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Re: Ponderings on Radiator Air Flow Through the AC Condenser

Originally Posted by Tootie Pang
On cars with AC, is all or most of the radiator inlet air supposed to be pulled through the condenser? The condenser seems much more restrictive than my radiator yet the all the fresh air from the underside and front of the car is brought up in front of the condenser by the plastic panels down there. In fact, the edges of the radiator and condenser are sealed and the bottom is the support so air can only bypass the condenser by going up and passed the face of it, over the top of it, then down into the space between the radiator and the condenser- only about 1" gap all the way over and in between. This does not seem like a good design.

In fact, when I turn on my AC, the temperature of the car rises by about 30-40 degrees, but the AC works great.
WOW, that is a huge increase in temperature. I think you've got some other problem. Are you sure your radiator is clean? I'm not just talking internally, I mean are all the fins clear of debris?
You wouldn't believe the kind of crap I've seen get stuck between a condenser and a radiator; it might do you good to check.
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Old Aug 25, 2020 | 07:41 PM
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Re: Ponderings on Radiator Air Flow Through the AC Condenser

No; ALL the air is supposed to go through the condenser. The AC can't work without it.

Some increase in coolant temp is normal when running the AC; but 30 - 45° seems like ALOT. My truck (04 LM7) with a 06 or so LQ4 fan on it doesn't vary by more than a couple of degrees. My 83 L69 T-top car, single electric fan, would stabilize at around 220° or so with AC (fan running continuously), and would cycle between 235° or so which would turn the fan on, to 210° or so which would turn the fan off, back and forth, for as long as it had gas, worst-case. In a MUCH hotter place at that time than where you are, that puts MUCH higher demands on the AC because of humidity (deep Southeast of the US). Let's say, 95°, bright sun, 90% RH. I would expect your car should do roughly similarly, and in the dry So Cal air at sea level, maybe a bit cooler.

Are you sure your fan is working as well as it should?

Last edited by sofakingdom; Aug 25, 2020 at 07:45 PM.
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Old Aug 25, 2020 | 08:50 PM
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Car: 1989 IROC Convertible
Engine: 350 TPI L98
Transmission: WC T5
Axle/Gears: 3.42
Re: Ponderings on Radiator Air Flow Through the AC Condenser

Good to know Sofa.

Everything is new (you name it, its new), just finished the Oaxilc Acid treatment on the cooling system. Big radiator. Fans are powerful dual 30-amp from a 3.8L ford V6 Windstar. They are shrouded and sealed in onto the radiator as a single assembly. High flow 180 deg stat, checked. High flow water pump.

It's not overheating, just gets higher than I like on the temperature gauge (above the "220" mark)

You know, I should check that temperature gauge vs the ECM.

Last edited by Tootie Pang; Aug 25, 2020 at 08:54 PM.
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Old Aug 25, 2020 | 09:33 PM
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Re: Ponderings on Radiator Air Flow Through the AC Condenser

My "new" AC condenser has much tighter fin density than the original, and my radiator core (DeWitt) is like 3" thick..... I'm moving to a modified Derale dual-fan setup that moves 4000 CFM and also carefully sealing everything with foam to ensure air flows through the cores and not around them.

GD
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Old Aug 26, 2020 | 01:35 AM
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Re: Ponderings on Radiator Air Flow Through the AC Condenser

Originally Posted by Tootie Pang
It's not overheating, just gets higher than I like on the temperature gauge (above the "220" mark).
You know, I should check that temperature gauge vs the ECM.
You are NOT referring to the stock temp gauge, are you?
That thing is an indicator - at best. There is no way that thing can ever be called a measuring instrument.
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Old Aug 26, 2020 | 11:52 AM
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Axle/Gears: 3.42
Re: Ponderings on Radiator Air Flow Through the AC Condenser

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Old Aug 26, 2020 | 01:04 PM
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Re: Ponderings on Radiator Air Flow Through the AC Condenser

Originally Posted by Tootie Pang
Yep , she's pretty , , , , , Your stock temp gauge , not so much ......
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Old Aug 26, 2020 | 02:23 PM
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Re: Ponderings on Radiator Air Flow Through the AC Condenser

Originally Posted by Tootie Pang
Good to know Sofa.

Everything is new (you name it, its new), just finished the Oaxilc Acid treatment on the cooling system. Big radiator. Fans are powerful dual 30-amp from a 3.8L ford V6 Windstar. They are shrouded and sealed in onto the radiator as a single assembly. High flow 180 deg stat, checked. High flow water pump.

It's not overheating, just gets higher than I like on the temperature gauge (above the "220" mark)

You know, I should check that temperature gauge vs the ECM.
If you have an infrared temp gun you can use that and check the temp @ the coolant neck where your t-stat is located.
As no emissions says those gauges are junk and mine will jump to 230+ and get stuck there sometimes.
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