2001 4.4i A/C blowing hot air

[Jakal702]

Hello all,
Yesterday my girlfriend was driving her 2001 X5 4.4i with the A/C on and all was well until suddenly the A/C began blowing hot air. I know that this could be caused by a lot of things, but recently the car had the A/C compressor, and condenser replaced. I know compressor is working because you can hear it engage, and I checked the refrigerant level and it was full. What could be causing the problem?
Thanks!

[andrewwynn]

You said you checked the level bit didn't say how.

The 01 I don't think had variable compression so that's a big help.

I have two '01 e53 and had the same symptom on wife's a month ago at the last 90 minutes of a 4 day trip, AC got weak and stopped putting out cold.

Went to put on the manifold gauge and noticed the high pressure side was leaking: the shraeder valve seat came loose. Poked it in a couple times to encourage the valve to re-seat and it worked. Added enough R134a to get about 45/250 psi at idle and all is well.

You cannot know If the refrigerant is topped off from only the low side and it's affected by ambient temperature.

Do you have a gauge set to read high and low psi? If not oreily auto will "rent" free. ( You buy and get a refund on return).

[upallnight]

Without anytype of pressure reading, since you girlfriend stated that it was working, but it stopped blowing cold air, I'm guessing the evaporator coil ice over, or you have a bad heater valve that is letting HOT water into the heater.

[andrewwynn]

Exactly what happened to us. Usually happens when freon is a little low. The difference between high and low pressure is proportionally higher and makes for colder evaporator. Get below 32 F and the conversate freezes eventually blocking airflow.

Symptom of this is: fan will be loud from spinning fast, but airflow will be weak and warm, also ten minutes with ac off will usually melt enough ice to get cool air even when AC is off. In fact when I determined the evaporator likely froze, I did exactly that and got cool air for the last 15 minutes of my ride home with the AC off.

If AC works for a while then stops each drive cycle that's exactly the symptom of frozen evaporator.

It does not take much loss of freon for this to happen. I probably added less than half a 12oz can to get back to normal. I probably went from 40/235 to 45/250 psi when I recharged. I also put Teflon tape on the cap on the high side to help seal If the valve since it's sketchy and I misplaced my vacuum pump so couldn't replace the valve so the special tool.

[Jakal702]

Today the car’s a/c began working again. I had her shut off the compressor for the past few days because I didn’t know what was wrong and I didn’t know if it could damage the a/c system further. I’m guessing it was just a frozen evaporator coil. Thank you guys for your help!

[Jakal702]

Should also add though, she had the compressor on until she saw me the next day and when I checked there was still no cold air... does it normally take that long for the evaporator coil to melt?

[andrewwynn]

No but was it ripe for foggy windows if she put on the defroster that will run the air conditioner compressor. Do you any event high-pressure side the pressure side figure it out