A/C performance improvement
A/C performance improvement How would I go about doing this? I just charged it. High and low pressures look about perfect. It just seems like the blower motor should put out more air.
It was 104 degrees here today. This isnt gonna cut it. Have anyone tried replacing the motor with a more powerful one or some kind of hot wire kit?
It was 104 degrees here today. This isnt gonna cut it. Have anyone tried replacing the motor with a more powerful one or some kind of hot wire kit?
What are you comparing it to? Other modern cars? For an early '90's car, the AC was great. Sure, it's not as good as the cars today but back then we sweat a little ...and we liked it! 
There are a few things that could degrade in the system over time but it's probably worth checking the mixing valve under the passenger dash panel. If it isn't shutting all the way, then you'll get hot outside air mixing in with your cool air before its delivered to the vents. Just take the panel off and turn the hot/cold dial quickly back and forth. If it's shutting all the way, you'll hear a thunk.
The other thing is that the vents (defrost, heater/underdash, etc.) are all vacuum actuated. If those vent louvers aren't closing, then you'll get pressure bled off and some cold air diverted to your feet, etc.
There are a few things that could degrade in the system over time but it's probably worth checking the mixing valve under the passenger dash panel. If it isn't shutting all the way, then you'll get hot outside air mixing in with your cool air before its delivered to the vents. Just take the panel off and turn the hot/cold dial quickly back and forth. If it's shutting all the way, you'll hear a thunk.
The other thing is that the vents (defrost, heater/underdash, etc.) are all vacuum actuated. If those vent louvers aren't closing, then you'll get pressure bled off and some cold air diverted to your feet, etc.
Sorry to piggyback on this post. I have an issue with my AC also. It blows cold and the air volume is usually great. Occasionally the air volume is largely diminished even when on high setting. I can hear the blower motor working. It seems to happen randomly. Any ideas ?
Joined: Nov 2001
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From: Schiller Park, ILL Member: #317
I have to disagree with some of the above.
- If you want cold, old A/C is where it's at - specifically an old R12 system working at it's full potential. It takes a long time at steady cruising rpms to get a newer 134a system to produce that kind of cold in my experience. Even at idle rpms, you could hang meat in the vent air stream of all the old R12 cars I've owned when they were fully charged. Only problem is that they rarely stayed at a full charge for long.
- My 2010 and 2012 daily drivers don't produce any colder air than the A/C system in my various 4th gen F-bodies, but their interiors do get cooler faster. In this case though, it's less about the temperature of the air coming out of the vents, and more to do with interior insulation and quality of window/door seals (and t-tops only further exaggerate this condition.)
If what's coming out of the vents specifcally doesn't feel cold even if the pressure readings are ideal then, as mentioned above, the "max" setting may not be working properly (blend door issues), thereby still adding hot air to the mix.
If the issue isn't vent temperature but just a still-warm interior no matter how cold the air stream seems to be, then it's more about that sealing/insulation issue I mentioned above.
If the issue is a lack of air flow from the vents then I'd look for obstructions/debris in the blower motor or path, or perhaps the motor is just dying.
- If you want cold, old A/C is where it's at - specifically an old R12 system working at it's full potential. It takes a long time at steady cruising rpms to get a newer 134a system to produce that kind of cold in my experience. Even at idle rpms, you could hang meat in the vent air stream of all the old R12 cars I've owned when they were fully charged. Only problem is that they rarely stayed at a full charge for long.
- My 2010 and 2012 daily drivers don't produce any colder air than the A/C system in my various 4th gen F-bodies, but their interiors do get cooler faster. In this case though, it's less about the temperature of the air coming out of the vents, and more to do with interior insulation and quality of window/door seals (and t-tops only further exaggerate this condition.)
If what's coming out of the vents specifcally doesn't feel cold even if the pressure readings are ideal then, as mentioned above, the "max" setting may not be working properly (blend door issues), thereby still adding hot air to the mix.
If the issue isn't vent temperature but just a still-warm interior no matter how cold the air stream seems to be, then it's more about that sealing/insulation issue I mentioned above.
If the issue is a lack of air flow from the vents then I'd look for obstructions/debris in the blower motor or path, or perhaps the motor is just dying.
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Seems like a lot of 80s and 90s stuff just had weak air flow, but my 01 TA is fine, so I'd think your 95 should be the same, or at least can take newer parts if the LT1 cars had worse air flow.
Check the voltage drop across the fan compared to your battery voltage. If you're not familiar with voltage drops, back probe both wires of the connector and check voltage while the car is running and fan is blowing at high speed. If it's more than a couple tenths lower than battery voltage, then resistance somewhere in the circuit is causing the voltage at the motor to be too low. It has to be connected and running. If you unplug it and check voltage at the connector, you just read source voltage. Also make sure charging system voltage isn't lower than it should be. Eliminate any voltage problems before doing anything else.
A new fan could possible blow harder than a tired old one.
Any air leaks in the evap box mean less air out the vents.
Check the depth of the hole the fan goes in vs the width of the "squirrel cage". There are some cases where a heat only blower is shorter than the blower for a AC car. If so it could have the wrong blower.
Last resort would be trying to fit a better blower from a different car. I'm planning to see what I can find that I can make work in my 2nd gens. They barely blow air.
Check the voltage drop across the fan compared to your battery voltage. If you're not familiar with voltage drops, back probe both wires of the connector and check voltage while the car is running and fan is blowing at high speed. If it's more than a couple tenths lower than battery voltage, then resistance somewhere in the circuit is causing the voltage at the motor to be too low. It has to be connected and running. If you unplug it and check voltage at the connector, you just read source voltage. Also make sure charging system voltage isn't lower than it should be. Eliminate any voltage problems before doing anything else.
A new fan could possible blow harder than a tired old one.
Any air leaks in the evap box mean less air out the vents.
Check the depth of the hole the fan goes in vs the width of the "squirrel cage". There are some cases where a heat only blower is shorter than the blower for a AC car. If so it could have the wrong blower.
Last resort would be trying to fit a better blower from a different car. I'm planning to see what I can find that I can make work in my 2nd gens. They barely blow air.
Last edited by t_raven; Jul 19, 2016 at 01:54 AM.
- If you want cold, old A/C is where it's at - specifically an old R12 system working at it's full potential. It takes a long time at steady cruising rpms to get a newer 134a system to produce that kind of cold in my experience. Even at idle rpms, you could hang meat in the vent air stream of all the old R12 cars I've owned when they were fully charged. Only problem is that they rarely stayed at a full charge for long.
My comments aren't so much about the stuff in the engine or the temperature of the air but more about the duct system in the dash. The ducts and vents on modern cars are so much better than what we had on American cars in the '80's and early '90's. The louvers seal much better and the vents are directed using computer-designed flow models so all areas of the car "feel" the effect of the air moving. The more efficient duct/vent systems can take the same blower power and get it around the car more forcefully and efficiently.
If what's coming out of the vents specifcally doesn't feel cold even if the pressure readings are ideal then, as mentioned above, the "max" setting may not be working properly (blend door issues), thereby still adding hot air to the mix.
If the issue is a lack of air flow from the vents then I'd look for obstructions/debris in the blower motor or path, or perhaps the motor is just dying.
If the issue is a lack of air flow from the vents then I'd look for obstructions/debris in the blower motor or path, or perhaps the motor is just dying.
Joined: Nov 2001
Posts: 34,629
Likes: 2,550
From: Schiller Park, ILL Member: #317
I haven't owned a car that used R12 since the late '90s, but I still remember the arctic blast they could produce - very similar to a January morning in Chicago.
My comments aren't so much about the stuff in the engine or the temperature of the air but more about the duct system in the dash. The ducts and vents on modern cars are so much better than what we had on American cars in the '80's and early '90's. The louvers seal much better and the vents are directed using computer-designed flow models so all areas of the car "feel" the effect of the air moving. The more efficient duct/vent systems can take the same blower power and get it around the car more forcefully and efficiently.
Now that I think about it... The A/C was probably in an early '70's Pontiac. The Cutlass was a convertible and we were windows-down all the time in that one!
I actually used a temp gun this past Friday to shoot the vents in my moms 2010 altima, the coldest reading was in the mid 30's. I recently changed my accumulator/dryer orifice tube and compressor in my 98 T/A. The coldest readings i got were the high 50's, this was at night, the altimas reading were on a 96 degree day. My A/C is the pitts in this climate no comfort in the summer months when the sun is out.
Joined: Nov 2001
Posts: 34,629
Likes: 2,550
From: Schiller Park, ILL Member: #317
I actually used a temp gun this past Friday to shoot the vents in my moms 2010 altima, the coldest reading was in the mid 30's. I recently changed my accumulator/dryer orifice tube and compressor in my 98 T/A. The coldest readings i got were the high 50's, this was at night, the altimas reading were on a 96 degree day. My A/C is the pitts in this climate no comfort in the summer months when the sun is out.
I've had no problem getting air much colder than that out of the A/C systems in my various 4th gens.
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The newer systems are much more complicated in how they operate. The 1st thing I would check is the evap inlet and outlet temps, on a hot day with the engine @2000 rpm the evap inlet and outlet piping should be in the 30's. If not then either you are low OR high on 134A OR the compressor is not loading up properly. The compressor has a regulating valve built into it, If it doesn't work properly ac performance will be poor.
I can tell you this, my 01WS6 blows 35 degree air out the vents I don't care how hot it is outside. Another problem you could have is too low on 134A, If the pressure goes below 32 degrees in the evaporator the moisture in the air will freeze the air passages through the evap causing poor air flow across the evap. Then you will have reduced air flow and poor cooling. Best bet is to find a GOOD HONEST AC person and let then check your system. Trust me GM would never build a car that couldn't freeze yer azz off even in 90 degree weather.
I can tell you this, my 01WS6 blows 35 degree air out the vents I don't care how hot it is outside. Another problem you could have is too low on 134A, If the pressure goes below 32 degrees in the evaporator the moisture in the air will freeze the air passages through the evap causing poor air flow across the evap. Then you will have reduced air flow and poor cooling. Best bet is to find a GOOD HONEST AC person and let then check your system. Trust me GM would never build a car that couldn't freeze yer azz off even in 90 degree weather.
dont overlook heat load, if u have t tops and theres blaring sun then its not surprising it feels like the ac cant keep up. you would have to look up the spec on ac performance for the car regarding btu/hr, then try to calculate the solar radiation input to the car which is more important than just outside ambient temperature. without good shades the glass t tops are a major heat source
Mine works pretty well but if I'm alone in the car, I don't even use the AC and I live in FL. I did have an issue last year when I lived in VA and it was pretty hot that day. I was driving for about 2 hours and my AC was working fine until it stopped blowing cold. I turned it off for about 15 minutes and it worked again... maybe it froze over due to moisture in the system? I dunno.
Sorry to piggyback on this post. I have an issue with my AC also. It blows cold and the air volume is usually great. Occasionally the air volume is largely diminished even when on high setting. I can hear the blower motor working. It seems to happen randomly. Any ideas ?
Mine has been a bit weird and I dismissed the issue because its an old car and I have another DD, however; SOMETIMES on a hot day it will get pretty cool even at idle, other times you have to drive it for awhile, and by awhile I mean several minutes before it gets cool. This is after a fresh recharge, btw I could NOT get it to take more than 45 PSI where as the refill kit said to fill it up with 60 PSI, it just wouldnt take more than 45 though.
Now here is where the REAL weird thing happens and this ALWAYS happens. When my A/C is on high or max and I am on the street and the A/C is blowing cold just fine, then I jump on an onramp and enter the freeway, for about 1 or 2 minutes, my A/C stops blowing cold air, infact it blows warm moist air for a few minutes and then the air changes back to cold, its colder than it was on the surface streets but still not freezing cold. Any idea as to why it becomes warm and moist for those few minutes when I get on the freeway?
Also sometimes I have noticed that the air will blow "cooler" if I turn the fan down from Max or High to about the second or third fan speed. It wont blow more air, but the air is definately colder that way sometimes.
My windows are all tinted and I also have shades on my T-Tops so I'm about as insulated as a 4th Gen can get.
Now here is where the REAL weird thing happens and this ALWAYS happens. When my A/C is on high or max and I am on the street and the A/C is blowing cold just fine, then I jump on an onramp and enter the freeway, for about 1 or 2 minutes, my A/C stops blowing cold air, infact it blows warm moist air for a few minutes and then the air changes back to cold, its colder than it was on the surface streets but still not freezing cold. Any idea as to why it becomes warm and moist for those few minutes when I get on the freeway?
Also sometimes I have noticed that the air will blow "cooler" if I turn the fan down from Max or High to about the second or third fan speed. It wont blow more air, but the air is definately colder that way sometimes.
My windows are all tinted and I also have shades on my T-Tops so I'm about as insulated as a 4th Gen can get.