2000 Mustang GT A/C issues

[Nifty]

So two years ago my mustang's A/C started blowing warm, so I hit it with a bottle of a/c refrigerant and everything worked great. I took the Mustang out this year and the air isn't blowing cold anymore. Here's the thing I have since filled it again thinking that it might just have a leak and that didn't fix it this time. The air coming out seems the be the hottest air possible, almost as if I have it set to heat. I could probably cook an egg by holding it up to it. So what are my option here? What do you guys think I might be looking at being the problem?

[Slow35th]

Did you fill it with the proper amount? Also they have an issue 99-00 where it will randomly not work. My 99 did it all the time.

[Nifty]

Nope. It doesn't work period. It acts almost as if I'm not changing it from the hottest setting at all. It still changes between the floor, the vents and the defroster but it just won't blow cold. It worked great after I did it the first time. It sat over the winter and did not work this year at all. I was hoping to find out it was something easy/stupid like a fuse that blows often or something.

[Gipper]

Is the compressor clutch even engaging? If the system is low enough on refrigerant, then the low pressure switch wont even let the compressor kick on. You have a leak. It's possible that the system is completely empty and just dumping in a few cans of R-134a is NOT the correct way to fix the problem. If refrigerant has leaked out, then air and moisture has gotten into the system. To properly charge the system requires a vacuum pump to remove air and moisture before filling with the correct amount of refrigerant. If you just dump refrigerant into the system WITHOUT removing air and moisture then you're just asking for problems in the future. Air will cause weird system operating pressures and the ability to cool properly will be affected. Moisture when mixed with R-134a refrigerant will create an acid which will corrode aluminum A/C components from the inside. If you want this fixed properly contact THIS GUY and I'm sure he will take care of you. I've never met him, but he seems to do a lot of work for board members and everyone is always very happy with his work.

Good luck!

[Akromix]

Is the compressor clutch even engaging? If the system is low enough on refrigerant, then the low pressure switch wont even let the compressor kick on. You have a leak. It's possible that the system is completely empty and just dumping in a few cans of R-134a is NOT the correct way to fix the problem. If refrigerant has leaked out, then air and moisture has gotten into the system. To properly charge the system requires a vacuum pump to remove air and moisture before filling with the correct amount of refrigerant. If you just dump refrigerant into the system WITHOUT removing air and moisture then you're just asking for problems in the future. Air will cause weird system operating pressures and the ability to cool properly will be affected. Moisture when mixed with R-134a refrigerant will create an acid which will corrode aluminum A/C components from the inside. If you want this fixed properly contact THIS GUY and I'm sure he will take care of you. I've never met him, but he seems to do a lot of work for board members and everyone is always very happy with his work.

Good luck!

I thought there was a dryer on car AC systems to prevent moisture in the system

[Gipper]

I thought there was a dryer on car AC systems to prevent moisture in the system

There is. Either a receiver/dryer, or an accumulator... depending if it's an orifice tube system, or and expansion valve system. The desiccant inside the dryer can only absorb so much moisture and then it becomes useless. A vacuum pump will lower the boiling point of moisture to a temperature well below ambient. If the vacuum pump runs long enough, the moisture will eventually migrate it's way out the exhaust port of the pump. However, if an A/C system has been sitting dead (empty) long enough then the desiccant is probably saturated, and from what I understand, removing moisture from the desiccant can be difficult. (with a vac pump) That's why they sell new dryers/accumulators. For $30-$40 bucks it's not worth screwing around with an old dryer if you suspect it's been saturated... in my opinion anyway.

[Akromix]

There is. Either a receiver/dryer, or an accumulator... depending if it's an orifice tube system, or and expansion valve system. The desiccant inside the dryer can only absorb so much moisture and then it becomes useless. A vacuum pump will lower the boiling point of moisture to a temperature well below ambient. If the vacuum pump runs long enough, the moisture will eventually migrate it's way out the exhaust port of the pump. However, if an A/C system has been sitting dead (empty) long enough then the desiccant is probably saturated, and from what I understand, removing moisture from the desiccant can be difficult. (with a vac pump) That's why they sell new dryers/accumulators. For $30-$40 bucks it's not worth screwing around with an old dryer if you suspect it's been saturated... in my opinion anyway.

I never said it wasn't a bad idea to replace the dryer. Just saying his system wasn't inoperable for a long time. I'm curious if he has a bad pressure sensor and as well question if the compressor is engaging.

[Gipper]

I never said it wasn't a bad idea to replace the dryer. Just saying his system wasn't inoperable for a long time. I'm curious if he has a bad pressure sensor and as well question if the compressor is engaging.

No, I never meant to imply that you said it was a bad idea. I also never meant to imply that he needs a new dryer. I was just trying to say there is more to properly charging an ac system then simply dumping in 2 or 3 cans of refrigerant.

It's very possible that he has a bad low side switch, a blown fuse, completely empty system, etc, etc. Hard to say without more info.

[mnstang]

it could be many different things, it's probably time for someone with the knowledge and tools for ac work to take a look at it.

[Nifty]

I just double checked and yes the compressor clutch is engaging. I'm just trying to avoid taking it to someone for something simple that would take 5-10 minutes to fix. Time is as important to the money to me. I'm not simply looking for the cheap way out, I just would fix it myself if it's not extremely difficult.

[Akromix]

I just double checked and yes the compressor clutch is engaging. I'm just trying to avoid taking it to someone for something simple that would take 5-10 minutes to fix. Time is as important to the money to me. I'm not simply looking for the cheap way out, I just would fix it myself if it's not extremely difficult.

Are you using an actual gauge while filling or is it one of those stupid yellow/blue/red with no readings gauges?

[slo5ohh]

Stuck/Broken Blend Door?

[Nifty]

Stuck/Broken Blend Door?

First thing I thought. I havent been able to confirm or deny that yet. And acromix yes Im using the correct gauge.

[Akromix]

First thing I thought. I havent been able to confirm or deny that yet. And acromix yes Im using the correct gauge.

What's low side pressure with AC compressor on?

[mnstang]

if it's blowing out full heat, you'd have to think there is a problem with the blend flap door being in the wrong position. why that would happen i have no idea, i don't know how that car works. i know foxes use a cable for the blend door, but vacuum for the various air outlets. yours might be vacuum though for the blend door also.. does it direct the air to the correct vents when that part is switched? i'm sure someone will chime in with more info.

you could see if the ac is working by holding the low pressure hose when it's on, it should be real cold.