OT: Auto AC

I hope their are some knowledgeable AC mechanics who can help me troubleshoot my auto AC.
Simply put, the compressor kicks on and stays on, but very little cool air is coming out. I thought if pressure is low, the compressor doesn't turn on. If very little cool air is exiting, I would think this is low pressure, but that's why I'm asking.
What steps should I start with to check the system? Should I just try a recharge first then see what happens?
Thanks
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 7/27/2012 5:56 PM, Meanie wrote:

check for a cabin filter issue. Never hurts to try.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

What year ?
My first step, buy can with gauge attachment. Careful, if there is some refrigerant in it, part of the tube should be cold in engine compartment. If there is some cooling going on, low fan speed, or obstructed air filter will make it cooler. Put temp gauge in duct and see if there is temp difference at different fan speeds.
Greg
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

When referring to fan speed, there isn't a separate fan for the AC, is there? The fan speed for the heating/cooling system is working fine as I increase from 1 to 4. The heat was great last winter. Unless there's something different, I think it's safe to assume the fan is fine.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
The same fan works the AC.
Why Greg wanted temps at different fan speeds. If there is low freon, or bad compressor, it might be colder at slower fan speeds.
Christopher A. Young Learn more about Jesus www.lds.org .
When referring to fan speed, there isn't a separate fan for the AC, is there? The fan speed for the heating/cooling system is working fine as I increase from 1 to 4. The heat was great last winter. Unless there's something different, I think it's safe to assume the fan is fine.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Check to see if you have good air flow. Fan could be bad. Air filter for the inside air could be dirty. If the AC refrigrant is low, the AC coils inside could be freezing up. To many this seems backwards, but with somewhat low pressure that is what hapens. See if you have good air flow to start with and then the air flow slows down or stops. The compressor usually has a low pressure cut off switch,but the pressure may not be that low.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
My sense, is that the OP should look for flow charts on the web. Or find a friend or neighbor who knows some about this.
Christopher A. Young Learn more about Jesus www.lds.org .
Check to see if you have good air flow. Fan could be bad. Air filter for the inside air could be dirty. If the AC refrigrant is low, the AC coils inside could be freezing up. To many this seems backwards, but with somewhat low pressure that is what hapens. See if you have good air flow to start with and then the air flow slows down or stops. The compressor usually has a low pressure cut off switch,but the pressure may not be that low.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

And you should too.
--
When the game is over, the pawn and the king are returned to the same box.

Larry Wasserman - Baltimore Maryland - lwasserm(a)sdf. lonestar.org
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
What kind of vehicle?
When you say "very little cool air". You mean the air is cool, but there is very little air flow?
You may find some trouble shooting flow charts on the internet.
Please don't go to the garage and say "I want a freon recharge". Say "the AC isn't making much cold air. Here, I'll show you what I mean..... walk over to the car with me...." and let the mechanic figure out what's wrong.
Christopher A. Young Learn more about Jesus www.lds.org .
I hope their are some knowledgeable AC mechanics who can help me troubleshoot my auto AC.
Simply put, the compressor kicks on and stays on, but very little cool air is coming out. I thought if pressure is low, the compressor doesn't turn on. If very little cool air is exiting, I would think this is low pressure, but that's why I'm asking.
What steps should I start with to check the system? Should I just try a recharge first then see what happens?
Thanks
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

'93 Honda Civic - Still has R-12 but I have replacement freon. I don't want to convert unless I really need to.

Yes
Will check.

Good advice.
Thanks
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Low air flow is LIKELY due to a very small leak in the evap - oil coats the evap, dirt sticks to it, and no air flow.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

A leak was my first thought. I have a can of dye and thought one of the first things to do was check for leaks before I tried anything. But I wanted to check with more knowledgeable people first.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Most of the time, when the freon is low. You get good air flow, but it's warm air. I'd check freon, last. From what you write, it's possible, but not all that likely.
Something to test: After the car has been turned off for a while. Take it for a drive, and turn on the AC. Does the air flow a lot at first, and then get less and less?
Christopher A. Young Learn more about Jesus www.lds.org .
A leak was my first thought. I have a can of dye and thought one of the first things to do was check for leaks before I tried anything. But I wanted to check with more knowledgeable people first.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 7/27/2012 4:56 PM, Meanie wrote:

I had to replace the expansion valve on the little Honda belonging to my friend's daughter. The darn thing was behind the glove box and a bit of a pain to get at. If you can get some one who understands R-12 automobile AC systems he/she/it can determine by the gauge readings if there is a restriction in the refrigeration circuit that could be caused by a defective expansion valve. After I replaced the TVX and refrigerant, the AC in the little car put out ice cold air. ^_^
TDD
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Some cars have a low side cut out, which might turn off the compressor if there is an expansion device problem.
Christopher A. Young Learn more about Jesus www.lds.org .
I had to replace the expansion valve on the little Honda belonging to my friend's daughter. The darn thing was behind the glove box and a bit of a pain to get at. If you can get some one who understands R-12 automobile AC systems he/she/it can determine by the gauge readings if there is a restriction in the refrigeration circuit that could be caused by a defective expansion valve. After I replaced the TVX and refrigerant, the AC in the little car put out ice cold air. ^_^
TDD
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 7/27/2012 8:23 PM, Stormin Mormon wrote:

It was a common failure on some of the Honda cars and unusual because it was a real live TVX valve like you might see in a refrigeration or stationary AC system. I got a good price on the valve and a restriction of course, on the high side will drop the low side pressure. I actually started disconnecting things and blowing nitrogen to help track down the restriction since I'd never worked on a Honda system before. I finally found the TVX buried behind the glove box. ^_^
TDD
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sat, 28 Jul 2012 05:36:57 -0700 (PDT), " snipped-for-privacy@optonline.net"

Your points are good. I don't recall the original post, but have fixed my own car A/C's for years. On one car (a '93 Grand Am) I first thought a new compressor was in order. But my gages found nothing wrong. After poking around I found the only problem was that the plastic cable connector on the mixer door had broken off.
--
Vic

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Site Timeline

Related Threads

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.