Air con slow to cool on passenger side

[bennys8]

Hello all,

When I turn on the max AC or turn on the AC at any fan speed the passenger side does not cool as fast as the driver side. It takes 5-10 minutes before it starts blowing out cold air. I tested this multiple times with the same results. In fact, the driver side air is cooler than the passenger side when the AC finally starts kicking in for the passenger side. I went as far as turning the temperature 5-8 degrees lower on the passenger side with the AC on and the fan speed set at max. The driver side still blows out colder air. All the vents are fully open and air is coming out of all of them. The passenger side just takes longer to blow out cold air and when it does the air isn't as cool as the driver side. Any ideas?
I have a 2005 X5 4.4 with 53K miles.

Thanks in advance,
Benny

[balongbalong]

Originally Posted by bennys8

Hello all,

When I turn on the max AC or turn on the AC at any fan speed the passenger side does not cool as fast as the driver side. It takes 5-10 minutes before it starts blowing out cold air. I tested this multiple times with the same results. In fact, the driver side air is cooler than the passenger side when the AC finally starts kicking in for the passenger side. I went as far as turning the temperature 5-8 degrees lower on the passenger side with the AC on and the fan speed set at max. The driver side still blows out colder air. All the vents are fully open and air is coming out of all of them. The passenger side just takes longer to blow out cold air and when it does the air isn't as cool as the driver side. Any ideas?
I have a 2005 X5 4.4 with 53K miles.

Thanks in advance,
Benny

you need to check your evaporator. changing this is an expensive and labor heavy job

[BrianX54.4is]

First check if the passenger side blows warmer with the A/C off and heater off (set to min temp but with A/C off). Could be that the heater valves on the passenger side are passing when they should be closed and re-heating the passenger side air when the A/C is on.

Also check that the cabin air temp sensors are not fouled with dust.

[Rockmelon]

Originally Posted by BrianX54.4is

First check if the passenger side blows warmer with the A/C off and heater off (set to min temp but with A/C off). Could be that the heater valves on the passenger side are passing when they should be closed and re-heating the passenger side air when the A/C is on.

Also check that the cabin air temp sensors are not fouled with dust.

Brian, how do you tell whether the heater valves on the passenger side are passing when they should be closed?

[haigha]

Originally Posted by Rockmelon

Brian, how do you tell whether the heater valves on the passenger side are passing when they should be closed?

I think it's in his first sentence: First check if the passenger side blows warmer with the A/C off and heater off (set to min temp but with A/C off).

However, I just tried this and it didn't exhibit the warmer air. I had my temps set to 60, the ambient temp was about 75 and I had the AC off. The air temperature all the front vents seemed the same.

See my thread here for my ideas on the problem and some good feedback from other members:

http://www.xoutpost.com/bmw-sav-foru...ht-thread.html

[BrianX54.4is]

Originally Posted by Rockmelon

Brian, how do you tell whether the heater valves on the passenger side are passing when they should be closed?

As haigha points out - set both sides to min temp with A/C off and both vents should blow at about the same temperature. If the passenger side blows warmer - then the heater valve or the control signals to the valve could be the problem. See haigha's other post/link.

The valves are a simple 2 solenoid operation with one coolant inlet (bottom) and two outlets (either side - 1 for driver side and 1 for passenger side) The solenoid has a rubber seat inside the valve body which can perish and break up. The debris can either block the outlet flow to the corresponding side heater when its valve is open (resulting in no/little heat to one side) or the bad seat can fail to stop the flow to the heater when its valve is closed (maybe the latter in your case).

You can feel the temp of the inlet and outlet hose connections to/from the valve body to see if one outlet is warmer. You can check the signals with a voltmeter at the valves. I think the valves are energised to close and de-energised to open. When the required cabin temperature is reached, the valves pulse open/closed at a variable rate to maintain temp.

If you determine that one valve flow outlet remains hot when its solenoid is continuously energised then you can strip the valve body to try to resolve the problem (or buy a new one).

The heater valve is item 3 below.

[haigha]

Thanks for the additional information, Brian. I did some testing with my infrared thermometer--which I just remembered that I have-- and found some interesting data:

Around the heater valve, the hoses all were around 150 F.

With the air on for about ten minutes, the vents read:

driver left: 50 F, middle left: 64 F, middle right: 78, far right: 79

The last two are about the same as the outside temperature.

So now I'm starting to question whether my problem is the heater valve.

[Rockmelon]

Originally Posted by haigha

Around the heater valve, the hoses all were around 150 F.

With the air on for about ten minutes, the vents read:

driver left: 50 F, middle left: 64 F, middle right: 78, far right: 79

have you tried refilling the freon? i understand that normal pressure range for inlet & outlet is around 1.5-2.2 bar and 12-22 bar. since driver side is cool and passenger side is warmer, the inlet pressure should be within normal range and outlet pressure should be on the low end. this suggests low freon and a possible leak somewhere. compressor should be fine since driver side is cooling. depending on how fast the same symptom recur after a refill, it just tells how bad the leak is. well i know of folks who would rather spend about $20-40 to refill freon every 2-3 months rather than change a leaking evaporator.

[Rockmelon]

Originally Posted by BrianX54.4is

If the passenger side blows warmer - then the heater valve or the control signals to the valve could be the problem. Attachment 42346

thanks, Brian. pls pardon my ignorance, i thought the X's aircon sys controls temp by regulating the blower fan speed when set to auto and according to whatever temp setting on the control panel? it does not really control the compressor which seems to be on all the time when cool ac is activated. the heater is only activated via a seperate push button on the control panel and switching to heater air duct is done manually via a rolling dial with blue and red color dots at the center air outlets? i noticed that heater air comes out only from the driver left & passenger right air outlets and not from the center air outlets.

[BrianX54.4is]

Glad to hear that the refrigerant top-up has restored good cooling to both sides - but it also suggests a small gas leak somewhere on your system (albeit might be years before you need to top up again).

Just to answer your previous post....

Originally Posted by Rockmelon

...i thought the X's aircon sys controls temp by regulating the blower fan speed when set to auto and according to whatever temp setting on the control panel?....

Yes, but in addition it regulates the rate of flow of hot coolant into the heater coil - (driver and passenger side independently as they do not have independent blowers).

Originally Posted by Rockmelon

...it does not really control the compressor which seems to be on all the time when cool ac is activated...

Correct, the compressor is not regulated for cooling capacity. Compressor speed is however constant (stabilised) independent of engine speed.

Originally Posted by Rockmelon

...the heater is only activated via a seperate push button on the control panel...

No, this button just activates a pre-set program to direct warmed air at full fan speed to the windsheild and side windows only (for rapid de-frosting/de-misting). It also switches off cabin air re-circulation and cuts out the independent rear passengers upper vents fan.

Originally Posted by Rockmelon

...and switching to heater air duct is done manually via a rolling dial with blue and red color dots at the center air outlets?...

This dial allows for tweaking the temperature of the air coming from the centre and side driver & passenger upper vents independently of the footwell and windshield vents for increased comfort (warm feet and cooler air to the face reduce driver fatigue).

Originally Posted by Rockmelon

...i noticed that heater air comes out only from the driver left & passenger right air outlets and not from the center air outlets...

These vents are the side windows vents (above the drivers and front passenger side vents). Warm air is available to all vents when the de-misting program is not active (according to the temperature and centre vent dial settings).

Note also that air is drawn through both the cooling coil and then the heater coil. With A/C on the air is first cooled and de-humidified and then re-warmed if necessary according to the temperature settings. With the A/C switched on you can still have warm air everywhere or have cold air to one side and warm air to the other side at the same time.

Did everyone check that driver and passenger temperature settings were set the same when they noticed the passenger side not blowing cold???