Automotive Air Conditioning Information Forum (Archives)

DACL on Tue July 19, 2011 7:53 PM

Year: 2004
Make: BMW
Model: X5
Engine Size: 4.4
Refrigerant Type: R134a
Country of Origin: United States

My wife's X5 is giving me a really hard time. The a/c will not cool at all until the truck has been run for about ten minutes. I have done a few things to repair this problem:
Replaced the compressor.
Checked the freon charge (I even tried varying it up and down 20% to make sure that was not the problem)
The clutch is engaging at engine start and stays engaged the entire time the car is running.
There is no aux. fan and the main fan spins up to full speed as soon as the a/c starts blowing cold.
When I check the pressure on the truck before the first start up the high and low sides are equal (no difference in pressure). When the a/c starts working the high side goes to where it should be and the low side drops.
I thought at first it was the reed valves in the compressor letting the compressor free-wheel and not compressing the freon, that is why I replaced it. But the new compressor made no difference, exactly the same symptoms.
When the a/c is working it works fine, but until the car has run for about ten minutes (my wife can sometimes get it to blow cold right away by revving the motor to the redline but I am not a big fan of that little trick) it simply blows hot air.
A lot of people want to blame the final stage resistor or the aux. fan but I have replaced the FSR and this car is not equipped with an aux. fan.

Karl Hofmann on Tue July 19, 2011 8:16 PM

Have you had a looksee at the front of the condenser, that is where BMW should have fitted the pusher fan...

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Never knock on deaths door... Ring the doorbell and run away, death really hates that!

DACL on Tue July 19, 2011 8:55 PM

Thanks for the quick response.

The 2004 4.4 liter did not come with a front mounted pusher fan (the BMW guys call it the aux. fan). BMW changed from a mechanical fan to an electric fan between the motor and radiator in this year, that was one of the first things I verified.

Tony

Karl Hofmann on Tue July 19, 2011 9:04 PM

Ah! I guess that the uk spec cars changed later than the us... In which case, does the electric fan start up as soon as the engine starts and the aircon is on or is there a delay? what is the pressure on the high side before the fan starts, is the condenser clogged with road debris or is there debris between the condenser and radiator? Is the vehicle equipped with iDrive? are the HVAC settings in the iDrive set to maximum cold?

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Never knock on deaths door... Ring the doorbell and run away, death really hates that!

DACL on Tue July 19, 2011 9:31 PM

Thanks again.

No the fan does not come on right away, it is delayed until the system actual starts cooling air. I can get it to spin up right away by unplugging the pressure sensor on the high side but normally it does not spin until the compressor starts actually compressing Freon and the a/c gets cold.

As far as pressures go both high and low sides are about 110 to 115 when I first start the car (it seems like they are equalizing for some reason) but when the a/c starts actually cooling they go to their working pressures.

The underhood area is clean of debris and is clean and undamaged. Both the radiator and condenser have been vacuumed out.

This vehicle does not have the iDrive function but the a/c settings have no effect, whether it is set for standard cooling or Max A/C has no effect on the delay.

Karl Hofmann on Wed July 20, 2011 6:45 PM

Ok, which compressor do you have? I'm hazarding a guess that you have a later clutchless compressor as opposed to the earlier cars which were fitted with a variable displacement compressor with a clutch..

If indded you do have a clutchless compressor, then I would be looking for a problem with the elecronics that control the compressor /refrigerant flow.

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Never knock on deaths door... Ring the doorbell and run away, death really hates that!

DACL on Wed July 27, 2011 1:30 PM

No, the compressor is the standard type with a clutch at the front.

I tried lowering the standing pressure fron 120 to 110 to see if that made a difference, as soon as I dropped the pressure the low side dropped to 35-40 and the system started cooling. But the next day the system did the same thing again, that is not cooling until the motor had run for ten to fifteen minutes.

I have no ideas.

bohica2xo on Wed July 27, 2011 5:43 PM

Ok, let's back up here. Some mixed info in the posts.

You state that the compressor engages at startup & stays engaged in the first post. Then in another post you state that the pressures are equal on high & low side with the engine running. Those conditions are mutually exclusive if the compressor is capable of cooling.

There is no unloader valve in the system. The only thing that controls the compressor is the A/C computer. The computer has several sensors & outputs that may be causing trouble, but the charge level is not the issue.

The first thing you need to do is recover the system, and weigh in a correct charge. Jacking the charge level around just makes more trouble to chase. Reducing the static pressure and having a result were coincidental. Put the refrigerant loop back to spec before you try to troubleshoot the control system.

Once the system contains the correct charge weight, start the vehicle, and wait for the compressor to start. Record the ambient temperature, and the high & low side pressures with the compressor running at idle. Then set the cabin fan to the highest speed, open the doors & run the engine @ 2000 rpm for 3 minutes. Record the pressures at 2000 rpm after 3 minutes. Post both sets of pressures here when you are done, along with the test ambient temp.

I would recommend the Mitchell repair manual available online if you do not have the FSM. Once you have the refrigerant loop in spec, we can help you work through the control system issues..

B.

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"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

tony1963 on Wed July 27, 2011 8:52 PM

Sometimes the expansion valve will not work properly and open too soon. Then, you have to run the system longer to build up enough pressure to force the liquid refrigerant through the opening.

Agreed that you should not be varying the charge by 20%. Fill the system to OE specs only. If you are within 5%, you're okay.

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Grove Automotive Group, Inc.

An Alabama Corporation

DACL on Thu August 04, 2011 3:46 PM

What I said is correct, the clutch is engaged and spinning when the engine is first started and the AC is turned on, but the pressures do not change, the high and low side remain equalized. That is the reason I replaced the compressor in the first place, I had thought it had a bad valve, but the new compressor does the same thing.

I will need to bring it to a shop because I have no way to fill by weight.

I do appreciate the input, thank you.

Tony

gregrsa on Fri January 25, 2013 8:40 AM

Hi, i currently have the exact same problem with my 2005 e53 X5 4.4 - takes about 10 min to start working, then is perfect. Hot starts the ac usually takes less time to kick in.
Were you ever able to find the fault?
Greg

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4.4 x5 e 53

munchkin29483 on Wed June 25, 2014 3:44 PM

munchkin29483 on Wed June 25, 2014 4:08 PM

A senior moment on last post.
My 2006 X5 has same problem and was wondering if anyone has anything new to add.
I even rebuilt the heater valve which didn't help.
Mine will work OK for days, meaning I get cold air at start-up, and then out of the blue on start-up it will blow warm air for a few miles and then start working.
Yesterday it was 90 degrees outside at start-up and no cold air for several miles.
Today it was 90 and at start-up I had cold air.
I have stopped several times when warm air is blowing and aux fan is not running and compressor clutch is engaged.
I have watched aux fan when its blowing warm air and the minute it starts to rotate air starts blowing cold.
When it starts blowing cold air I can turn it off and on all day long with no cold air problem.
I have let it sit several hours after cold air is blowing and restarted with no air problem.

mk378 on Thu June 26, 2014 10:23 AM

It appears you have a variable compressor that is not working all the time. When the compressor is stuck at zero displacement, it will spin but not compress. The fan is pressure activated, so no compression-->no fan. Replacing the whole compressor as a unit is the best bet rather than tinkering with the internals.

ethem11 on Sun July 13, 2014 2:37 AM

I am having same problem with my BMW e53 2005 3.0.

Ac is not working 8 to 10 min and than starts cooling. AC compressor is always engage from start.

I was thinking to replace the compressor but after reading your comment you said you replace it but it did not help. I wonder if anyone having same problem and found a solution ???

ethem11 on Sun July 13, 2014 2:38 AM

did you find any solution ?