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Takes too long for A/C to blow cold air

joelja208 on Tue August 25, 2009 2:48 AM User is offline

Year: 1989
Make: Toyota
Model: Corolla
Engine Size: 1.6
Refrigerant Type: r134a
Ambient Temp: 90-95F
Pressure Low: 30
Pressure High: 250
Country of Origin: Philippines

I seem to be having issues with my car's A/C.

First of all the car got into an accident sometime ago so the lines are new and are somewhat shorter than the original line(around 4-5 feet shorter at the high side, 3/8"). I have no idea how much freon the original system takes(R-12) but I'm guessing around 20oz? Give or take 2oz. For R134a I know I have to charge a little bit less and I have to take in to consideration that my lines are also shorter.

I charged it with about 18oz(clear on the sight glass) of r134a and got the following results.

Ambient 78-83F
Low = 20
High = 220
Vent = 45F @max fan setting

Ambient 90-95F
Low = 50
High = 270
Vent = 70F @max fan setting

I figured I might be a little bit overcharged so i reduced the charged to around 15oz(almost clear sight glass) and got the following result

Ambient 90-95F
Low = 30
High = 250
Vent = 60F @max fan setting

Now my problem is, it its parked outside during the day(90-95F), it takes too long for the A/C to cool. It's really hot over here and my car doesn't have tints on. Is there any way I can improve my A/C's performance?

I tried getting readings from my other car(a Nissan Van), and as soon as I turn the A/C on the gauges read 25 low and 180 high in as little as 20 seconds and the vent blows really cold air. Same exact conditions, car left outside and ambient is 90-95F.

Dougflas on Tue August 25, 2009 5:39 AM User is offline

was it charged into a vacuum? Was it filled with 12 or r134 before the accident? This vehicle may not be a good candidate for r134. Spray the condenser with a garden hose. Does the high side drop really quick?

NickD on Tue August 25, 2009 9:22 AM User is offline

Easiest systems in the world to verify for leaks, just run the AC at 2,000 rpm on a warm day and peek at the sight glass for more than the normal amount of bubbles, correct charging is when at the same speed, R-12 is added so the bubbles just disappear, only would pull out the gauges if that doesn't do the trick.

With R-134a, you have to be able to judge the amount of foam you see in that same glass, even I am not that good at that. And gauges are a must so your dual function switch doesn't go crazy. Really don't have have to be concerned about your evaporator thermal switch, sucker will never freeze up with R-134a, could stick with R-12, or get a complete R-134a conversion kit. These systems were never really good even when tuned up properly and with R-12. We don't have the ocean effect like they do in Japan.

joelja208 on Wed August 26, 2009 10:10 PM User is offline

Quote
Originally posted by: Dougflas
was it charged into a vacuum? Was it filled with 12 or r134 before the accident? This vehicle may not be a good candidate for r134. Spray the condenser with a garden hose. Does the high side drop really quick?

Yup, it was charged into a vacuum. It was R12 before but we did a proper conversion, we even changed the compressor.

Update, I got all of the freon out and I vacuumed it for an hour at -30 and left it overnight(no leaks). Charged 17oz, and I seemed to have gotten pretty decent results

Ambient = 80F
Low = 20
High = 190
Vent = [email protected] fan setting

Ambient = 90F
Low = 25
High = 220
Vent = [email protected] fan setting

I'm pretty happy with it now but somehow I'm still a little bit sketchy about the amount of freon I put in. I just read the capacity listings and saw that my car took 27oz of R12, how much is that for r134a? Around 24oz? So if I charged 17oz since I compensated for my shorter high side line, did I charge a bit too little? I mean, isn't 7oz for 4-5feet of 3/8 tubing a bit off? Sight glass is pretty clear, minimal to zero clouding.

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