So I have a 1990 LX Sedan I just bought and the air conditioning just blows hot air. I've just recently got into working on my car, so i'm new to almost all car related projects. What could my possible problems be and assume you are talking to a 12 year old, cause I dont know much about A/C's? I am pretty good with tools but a diagram or pictures would definately help. Thanks all!

P.S. Before you say search, I did but I dont know a condensor from anything else, so I was hoping someone could put it in simple terms.


Modified by rugimpy at 1:08 PM 6/27/2008

 

the AC is one of the few systems in the car that one really should not service oneself because well it requires some pretty specialized tools such as a heavy duty deep vaccum pump, high pressure hoses and gauges, and fittings, etc.

Your A/C is blowing hot air because either the compressor is not doing its job, or the refrigant has all escaped out. You need to determine which one it is, and go from there.

The service manual can help you determine if its your compressor or lack of refrigant. But repairing it may be beyond your ability. If it's the compressor, the system will need to be evacuated, sealed off, and the compressor replaced, and then the entire system will need to be drawn to deep vaccum, sometimes several times, to purge everything before being charged with refrigant. If it's a leak, it needs to be found with a leak detector, and then purged again and recharged.

The dryer should also be replaced when doing either of those.

Janos

 

Wow, and im assuming thats gonna cost me a bit, especially in ths summer. When I push my A/C button, the light doesnt turn on. Any chance it could be a fuse?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Janos Lin &raquo;</TD></TR><TR><TD CLASS="quote">the AC is one of the few systems in the car that one really should not service oneself because well it requires some pretty specialized tools such as a heavy duty deep vaccum pump, high pressure hoses and gauges, and fittings, etc.

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I have to disagree Janos. I do all of my own AC work.

I use a vacuum pump similar to this one : http://www.harborfreight.com/c...96677

I put a rebuilt compressor kit I bought off of ebay in this year and my AC actually cools quite well even running R134a.

Of course I've been doing this for awhile now so I'm not sure if this is a noob project.

 

Well, as a noob, what are some of the things I can check first that would be in my realm of work just to check some things off that arent the problem?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Janos Lin &raquo;</TD></TR><TR><TD CLASS="quote">
Your A/C is blowing hot air because either the compressor is not doing its job, or the refrigant has all escaped out. You need to determine which one it is, and go from there.
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There are more possibilities for the a/c not to blow cold air. It could be from the compressor, to a radiator fan wired backwards........

my advice if you want to do it yourself:

1. Find out if your system has been retrofited from R12 to R134A. If its still R12 and it has freon on it, dont remove it because it is very expensive....

2. Rent some a/c gages at autozone for free after the deposit, and measure the low and high side of the a/c lines. The low side is the bigger diameter line and its on top of the high side line next to the firewall. The high side is the low diameter line.

3. Verify that the compressor is kicking and if both of your fans are working. If the compressor doesnt kick, this means that either your system doesnt have freon or maybe bad relay/fuse or bad compressor.

 

Yours did blow cold air occasionally, and frankly, wiring it backwards doesn't happen that often. If the wiring's been messed with, and something doesn't work, go back to the wiring. Compressor malfunction or lack of refrigant are basically the 2 main reasons for the lack of cold air. It could be the air mixture valve, but lets find out about the A/C system first.

I'm not saying nobody should do theirs. If you have the knowledge and training, be my guest. But not everyone has the equipment or training. Besides venting the refrigant to air isn't a good idea anyway. Need to have the right equipment to recover it. R134A can cause asphyixation, and if it gets too hot, it can become toxic. Besides it's looking like it's sale and use is going to be restricted soon anyway.

Janos

 

Thanks guys, im starting to get an idea of how to attack it. Anyone have pictures or diagrams to help?