Air Cond icing up
 

Hi Guys I have a problem that keeps happening whenever we go on a trip. I will define this by calling a trip longer than 3 hours driving. The air works faultlessly at all other times. It seems that the system is icing up because the fan is still working but no air is coming out of any of the air vents. Are there any fix's for this problem.

Thanks

Check the high side and low side pressure, Your low side pressure could be too low causing the evaporator to ice up.

thanks I will have to google that, I dont know what you mean but thanks for the tip

The other component is the expansion valve, but the system needs to have the refrigerant removed in order to replace it.

Are you running with the air recirculation on? It's the button on top of the ac button.

Does anyone know how much is the low and high pressure is supposed to be?

I think I have a similar problem. On longer trips, the AC is blowing warm air at times. Also, I can feel the compressor turn on and off and I would like to check the pressures. Thanks.

Check for evidence of leaks (oily residue) where the system pipes connect to the condenser and compressor. It is not unusual for the O-rings in those fittings to deteriorate. An inadequate refrigerant charge will cause the evaporator to be "super-cooled", resulting in the ice up condition.

2002 X5 3.0 236,000 miles
2004 325i 105,000 miles

the fan is working but no air is coming out... this is an actual symptom... the statement that it "ices up" - is it a fact that you observed or a specualtion, that you "think" might be happening?

the reason i am asking, if you observed the ice, than the suggestions provided are correct, if you did not observe the ice but suspect that is what causing the issue, than we should see why the air is not coming

Thanks for the pdf ABLE. I will look through it.
Terminator, you are right. I did not see the ice building up, and not wanting to start a new thread, I just "tacked" onto this one.

This has only happened on a long trip we took, after about 1 hr of driving.
It doesn't happen while driving in the city.

And in my case, air still comes out of the vents, it's just not that cold. I had to keep on 60 for it to be semi-cold. After I turned off the compressor for about 1 minute, the AC came back on. Even then I could feel it go "in and out". Not sure if that's normal on long trips.

I do not have experience on your vehicle - but I have found on others that if the inside (recirculate) filter is dirty it can have the effects you're experiencing. (Does your vehicle have an inside and outside cabin air filter? - are they clean?)

The outside cabin filter, the one in the engine bay is new. I don't think I have another cabin filter. Does anyone know if there's another cabin filter aside from the one close to the windshield?

I don't think your 04 X5 E53 has one - this is what I found on the recirculating filter:

Fresh Air/Recirculating Air Filters
The E9X is equipped with a carbon activated microfilter which is accessible from the engine compartment.
Fresh air is drawn in via two filter elements in the intake area in front of the bulkhead. The recirculated air is drawn in at the side by the blower via separate recirculating air filters.
Fresh Air Filtering
A particulate filter or a micro/activated charcoal "combination filter" is also used on the E70 fresh air intake. The particulate filter (also referred to as a microfilter) removes dust, pollen, soot and other dirt from the fresh air that is needed to control the climate of the vehi- cle.
The adsorption filter (activated charcoal filter) has the job of remov- ing the pollutants (hydrocarbons, acidic gasses) that mainly occur in high concentrations under smog conditions from the fresh air used the vehicle’s IHKA system.
Recirculated Air Filtering
A new type of honeycomb filter is used in the recirculated air intake.
The versions for fresh air particulate filters can also be used for fil- tering recirculated air, but are used for cleaning the air in the pas- senger compartment.
Filter types and equipment in the E70. All filters are electrostatically charged during manufacture and have the characteristic of attract- ing particles and holding them in, therefore cleaning the air.
The performance figures of an adsorption filter are initial pressure loss, particle separation, dust storage capacity, gas adsorption (such as n-butanes, sulphur dioxide, toluene) and are independent of the filter surface and the air-mass flow.
In order to be able to cope with customer specific filter usage and associated change interval increases and reductions, the filter change intervals of the E70 have not been stored in the CBS (Condition Based Service) system.
Note: The filter change intervals can be found in the relevant service literature.

:iagree: First step is to check the pressures. If you haven't done it before or you don't have the proper equipment it is not a good first time DIY. A good auto parts store has the equipment to rent or will check it for you, free of charge.

I plan to get the pressures checked hopefully tomorrow. Does anyone know what the "best" pressures are for the X5. I know they can vary, but just wanted to get some input about that. Thanks

Thanks for the replies so far. just to clarify my car, the fan still runs, at all speeds. no air will come out of the vents at any setting, e.g. screen, floor, face. if we stop the car and have lunch all will work fine after the break.. It doesnt happen all the time, sonar three times in a year, but it is allways after a bit of a drive.

Put a digital thermometer in the center vent and monitor the vent temp. If it is close to 0C or 32F your evaporator is icing up. Once it has ice up look at the vent temp again. I bet you it close to 0C or 32F.