QuestionHi I'm having trouble with my A/C, I was hoping you could help me with this problem. Well my problem is my A/C is blowing hot air all throughout the car even when I put the A/C to the lowest temperature. I put refrigerant in yesterday and it worked for a little while then it went back to blowing hot air. Could you tell me whats wrong with my car, and hopefully how to fix it?
thanks,
Agosto
AnswerAgosto,
It blows hot, you add refrigerant-it blows cold, then blows hot again shortly after.
It sounds as though you have a leak in your system. and depending upon how much you put in and how long it took to leak out, it sounds like a pretty big one.
The easiest way to locate it is as follows...
Check your pressure. One of the cheap gauges from autozone is fine. If you have any pressure whatsoever in your system it is enough. The lower the pressure though, the longer it will take. If it completely emnpty, then you definately have a good sized leak. If you have absolutely no pressure whatsoever, pressurize the system with nitrogen, or if you do not have access to nitrogen, you can put some refrigerant in and it will pressurize it also. This may cost a bit more, depending on how long it takes to find it. But DO NOT put any type of compressed air or any other gas in the system. This will cause, at the least, acids to form in your compressor oil, and at the worst, it can explode.
Ok, once you get pressure in the system... With the vehicle off...
First listen. If it is a sizable leak, you may hear it hissing from somewhere. After that with a spray bottle of soapy water (windex works well also, spray the area you here the hissing from. You will see bubbles form at the location of the leak. If you do not hear it, with the spray bottle, start at your compressor where the lines are coming out of it. Spray it down with the bottle, watch the connection for a few seconds for bubbles to form. If it is not there, begin tracing the lines through the system spraying every connection where lines join to something. The most common point for leaks is at joints a fittings. As the vehicle runs, the vibration can loosen the fittings. If the leak is from a joint, disconnect it, make certain the o-ring is in good condition, replace it if necessary, reconnect it tightly.
If you are unable to find a leak at a joint then move to your condensor in front of the radiator. Make sure that you spray down the circulation loops on the side of the condensor as well as the fins. If you still find nothing anywhere in the engine compartment, then it gets to the annoying part. You have to do the same thing to the evaporators and lines in the cab. Don't forget about the rear evap. In the 99 I believe it is in the driver's side fenderwell cover. You will have to remove the trim panelto access it.
Whereever you findhte leak, you will need to either tighten the line or replace the component. Once you have dont this, you will need to allow a vaccuum pump to evacuate the system for at least 30 minutes preferable about an hour. Any A/C shops can do this. Once the vaccuum is turned off, you need to ensure that the system stays in a vaccuum for at least 10 minuites. If the needle rises, you have another leak that needs to be found. After all of the leaks are found and repaired you just need to have the system charged.
If all of this is too much to bother with, Everything start to finish (minus replacement components) should cost you no more than about 150 bucks at a shop. And they will probably use a dye in the system to find the leak, tell you to take the truck and bring it back a couple days later.
I hope I was of a little help. If I can do more, just let me know.
