A/C conversion TOO cold?!
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Joined: Apr 2001
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A/C conversion TOO cold?!
R12 to R134a conversion two years earlier on dual air Aerostar was successful, producing center vent temps of 38 degrees. (highway) Recently the front orifice tube was plugged and I replaced it. System holds 60oz R12 coolant but from first efforts 56oz R134a proved optimal.
This time, after adding 56oz coolant, the center vent temps have dropped to around 33 degrees (highway driving). Previously it took around 2-3 minutes to feel the cold air from the vents on hot days, but now it flows after only 30 seconds.
Ambient: 90 degrees High side: 275 Low: 35 Front o-tube
range rear unit: brown (same as first time) Front center vent: 33 degrees rear vent: 38 degrees (both highway)
Pressures seem reasonable but I do notice the compressor feels like it carries more of a 'load'. No noises but if the A/C if on when shutting down the engine, it stops dead immediately, no residual inertial revolution as without A/C on.
At temps this low in the evaporator I would expect icing, but none noted yet after serveral drives of 35 minutes duration. Of course there is very low humidity in Colorado this time of year which may be the reason.
While all the cold air is appreciated, why would this system be running so cold?
This time, after adding 56oz coolant, the center vent temps have dropped to around 33 degrees (highway driving). Previously it took around 2-3 minutes to feel the cold air from the vents on hot days, but now it flows after only 30 seconds.
Ambient: 90 degrees High side: 275 Low: 35 Front o-tube
range rear unit: brown (same as first time) Front center vent: 33 degrees rear vent: 38 degrees (both highway)Pressures seem reasonable but I do notice the compressor feels like it carries more of a 'load'. No noises but if the A/C if on when shutting down the engine, it stops dead immediately, no residual inertial revolution as without A/C on.
At temps this low in the evaporator I would expect icing, but none noted yet after serveral drives of 35 minutes duration. Of course there is very low humidity in Colorado this time of year which may be the reason.
While all the cold air is appreciated, why would this system be running so cold?
Logistics Pro
Joined: Jul 2003
Posts: 3,595
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From: Lawton, Oklahoma
A/C conversion TOO cold?!
If you can get air that cold with a low side of 35 then its a miracle. More likely your thermometer is out of calibration though. With an outlet of 33 the core should be freezing solid.
Freshman User
Joined: May 2003
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A/C conversion TOO cold?!
Thats a coefficient of performance through the roof, you've done something special there...did you relocate the compressor inlet tubing? If it was moved to a more insulated area of the engine that would slightly effect output temperatures??
New User
Joined: Dec 2003
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Most people don't realize that having too little coolant in your ac can actually make it run colder if it's not low enough to make the compressor cycle. That's because the low pressure side of the pinhole is too low. Put the right amount in. The coldest results aren't the optimal ones. Your core is going to freeze when the humidity takes off
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