2003 Ford Windstar A/C

[CharityDC]

2003 ford windstar
So I start the van, a/c is on then it lets out a very loud hiss (like your filling a helium ballon up) and lets out smoke/mist from under the hood. It did that everytime i started the van while I was out today. Everytime it did that I turned off the A/C and it quit. Therefore it let out all or most of the freon because it was no longer cold at the end of our long day out. My husband put a new can of freon in and it was blowing cold (not freezing cold as i'd like), then after we left football practice i forgot to turn the a/c off before i started the van and it did it again.

Frustrating to remember to turn the a/c off everytime!

We had a New Compressor put on June 2014, along with orifice tube and o rings while we were in Ohio on vacation because the one we bought from auto zone in 2012 was the wrong one, had it vacuumed out and refilled by a reputable mechanic my grandmother has been using for years.

It did this after they put the new compressor on but they said it could be a clog further down the line or the rear a/c not working that could be causing it to do this. It went from July last year to the middle/end of July of this year without doing that at all and it was ice cold.

What can be causing this issue? Could it be because the rear a/c is not working at all? Please, let me know any information i could check on it and hopefully fix the problem.
Thanks!!!

[brcidd]

Most likely lack of air across condenser when sitting still on start up-- does condenser fan operate?

[CharityDC]

Originally Posted by brcidd

Most likely lack of air across condenser when sitting still on start up-- does condenser fan operate?

Where is the condenser fan? I'm going to assume thats one of the fans in the front of the radiator?

My husband just told me when he was filling the Freon, the a/c clutch kept kicking on and off instead of staying on like its supposed to?

[scubacat]

There's a leak somewhere. Get the cheap yellow glasses and UV light from harbor freight or an auto parts store and look for the leak. Most cans of freon have the UV dye in it so with the glasses and the light you should be able to find it.

[CharityDC]

Originally Posted by brcidd

Most likely lack of air across condenser when sitting still on start up-- does condenser fan operate?

Ok, So i went out this morning, turned the a/c off, started the van and neither fan in the front turned on, Turned the a/c on and the 2 fans immediately came on. It looks like both are working correctly.

What would I look at next?

[scubacat]

If you're adding freon and hearing hissing, it's a LEAK. Repair the leak and evacuate, vacuum, and recharge the system. I recommend taking it to a mechanic for that.

[CharityDC]

Originally Posted by scubacat

If you're adding freon and hearing hissing, it's a LEAK. Repair the leak and evacuate, vacuum, and recharge the system. I recommend taking it to a mechanic for that.

The hissing (like your filling up a helium balloon, LOUD) only starts when i start the van with the a/c on, turn the a/c off it quits, turn the a/c back on and it don't do it.

It don't do that while filling it up with freon. Only when i start the van while the a/c is on.

[scubacat]

It could be a bad seal in the compressor. Was it a rebuilt unit? If you're having to add freon, there's a leak. It could also be a very slow leak except when it's running. Freon leaks can be tricky to track down, but fact is, if you have to add freon at all, it's leaking somewhere!

[CharityDC]

Originally Posted by scubacat

It could be a bad seal in the compressor. Was it a rebuilt unit? If you're having to add freon, there's a leak. It could also be a very slow leak except when it's running. Freon leaks can be tricky to track down, but fact is, if you have to add freon at all, it's leaking somewhere!

No it was a brand new compressor. Yes it leaked out every time i started the van with the a/c on and it spit out freon. It's not leaking like your oil would, its spraying it out somewhere from the compressor once the van is started while the a/c is on.

It only just started doing this the end of July. It has gotten really hot down here.

[scubacat]

I'd take it back to whomever replaced that compressor for a warranty replacement. They're often covered for 3 years (including labor).

[CharityDC]

Originally Posted by scubacat

I'd take it back to whomever replaced that compressor for a warranty replacement. They're often covered for 3 years (including labor).

Thanks but that's not possible since I live in Florida and we had it replaced in Ohio.

[scubacat]

A local mechanic should be able to submit the warranty claim for you if you have the invoice from your previous repair.

[tomj76]

(1) You have a leak, a strange one, but still a leak. It isn't clear how it would leak only if the a/c is on when the engine is started. Maybe if I knew where it was leaking I could venture a reasonable guess.

(2) The Windstar A/C system is supposed to cycle like your husband noticed. It is different from other automotive A/C systems. I'll explain the difference. When an A/C system is running and the compressor is running at maximum capacity, the energy stored in the refrigerant will continue to fall if the cooling demand isn't high enough because energy is being taken out (at the condenser) at a faster rate than it is being added (in the evaporator). This is bad for several reasons, it degrades lubrication of compressor, it causes the system to run colder, it can result in "slugging" of the compressor, it causes the system to run inefficiently... However, if the pumping capacity of the compressor were reduced in the design, then the system wouldn't work well on extremely hot days. To deal with this engineer designed systems that only pump as much as needed for the weather conditions.

GM engineers developed a variable displacement compressor which changes the amount of refrigerant that gets pumped. On hot days the full amount is pumped, but on cool days the compressor pumps a smaller amount of gas during each cycle. The system maintained at the optimum operating point.

A different approach is used on Ford vehicles. Ford uses a pressure cycling switch that monitors the pressure at the outlet of the evaporator and turns off the pump when it gets too low. This also protects the compressor when there is a severe leak. Initially the low side pressure is ~60 psi. When the compressor is engaged the pressure starts to drop (since the switch is on the low pressure side of the system). When the pressure falls below ~30 psi the switch opens, the compressor disengages (clutch) and the AC "runs" on the flow through the evaporator as the system pressure starts to equalize. Eventually the pressure rises to about 35 psi and the switch closes, the compressor starts pumping again, and the low side pressure starts to drop again. This process repeats indefinitely while the ac is turned on.

There is also protection against TOO HIGH system pressure, for cases where heat is not getting removed from the system (such as if the condenser fans fail to run). It might be built into the cycling switch, but I think it's on a separate pressure switch.

The cycles will be very short when the system is low on refrigerant because the pressure will rise very quickly after the pump is turned off. The Ford Service Manual gives the cycle time for various ambient temperature conditions as an aid to properly recharging the ac system.

[CharityDC]

Thanks for the Information I'll reread it in a bit. But it is def spewing out of the compressor....is their a pressure valve or something on it? It has not done it since i have been turning the a/c off before i start the van, then i turn the a/c on and all is well. So far its only doing it when the a/c is in the on position and the van is started. Thanks for ev1's help in this issue.
I also have the issue of it switching from front vents, to defrost to floor vents when the engine is under load while going up a hill or passing cars. I found the thread to check that out, and will soon.

[tomj76]

Sounds like the compressor is defective.

I can only think of one guess of an explanation, but I don't think it makes sense.

Here it is anyway: When the engine is running, the pulley on compressor is spinning, but the clutch does not engage it to the pump. When the AC is turned on the clutch engages, and the spinning pulley resists any "twisting" that would deflect the pump shaft and cause a leak at the seal. On the other hand, when the engine is started, if the clutch engages too soon (or is already engaged), then the pulley may not be spinning as fast, and the pump shaft is deflected enough to allow a leak. Once it is deflected the leak regulates the high side pressure preventing the low side pressure from reaching the level needed to shut down the pump, so the compressor just keeps pumping away until most or all of the refrigerant is lost.

Hopefully you at least have warranty coverage on the compressor unit. Check (or have the technician check) that the compressor clutch doesn't engage until the engine is running.