AIR CONDITIONING PROBLEM

AUssiePaul · #1 07-07-2009, 02:41 PM

I have a 2005 BMW X5 3.0. I live in Texas and as you know, it can get

: FREAKING HOT

: here in summer and that is starting to happen. Over the last couple of weeks I have noticed that the AC has been taking longer and longer to kick in and start putting out cold air, and when it does the air is not as cold as it should be.

I have checked the refrigerant level with 3 different gauges and have verified that there is enough refrigerant in the AC system. I have let some pressure out of the system and regcharged it back to the required pressure, which has helped a little, but not a lot.

I have made sure that the compressor is running and that the car is at operating temperature. The temperature adjuster on the center vents is set to cold and the AC is set on MAX.

Does anyone know what the issue may be or if there are any known issues that may be causing this. I am fairly mechanically literate so I am hoping that this is something that I can fix myself.

Any advice would be much appreciated.

Cheers,

Paul

Werewolf · #2 07-07-2009, 02:53 PM

check the thermostat and compressor

anerbe · #3 07-08-2009, 09:08 AM

also check aux fan to see if it's running. does it change when you drive on the highway? how does the compressor look? has the drier/collector/filter on the condenser been replaced? sometimes a clogged filter will slow down and reduce pressure within the a/c loop (although this is more rare)

could also be blend doors (air door in HVAC not completely routing from evap), the txv, etc...

start simple first. good luck!

AUssiePaul · #4 07-11-2009, 04:06 PM

Okay, it looks as if the Auxiliary Fan on the front of the radiator isn't coming on.

I have looked in the front and rear fuse boxes but couldn't find a fuse for it. Is there a fuse or relay located somewhere else on the car that I can check?

AUssiePaul · #5 07-11-2009, 04:39 PM

UPDATE.....

It looks as if the auxiliary fan works, but only kicks in when the engine temp gets up there.

I am guessing there is a switch/relay somewhere that should turn the AUX fan on when the AC is on.

Any ideas on where I need to start to fix this?

AZX54.4 · #6 07-11-2009, 06:33 PM

I live in Phoenix, AZ and have an 05 x5 4.4i. I had a similar problem with mine and it was determined that the evaporator is leaking/failing. The car would blow warm air at start up. By the time I drove to the end of the block the AC would start blowing cool air but never as cold as it should be (I had my 02 x5 for comparison with a perfect AC system) I took the car to the dealership and an evac/ recharge was done to the system. They put in nearly a lb of freeon. After a week of using the car they did a follow-up inspection of the AC system to check for leaks. Thats when they determined it was the evaporator. There is a trap door behind the carpet on the side of the drivers foot well. Behind this piece of carpet is where the trap door to inspect the evaporator is. There is one screw by the gas pedal on the carpet and then it pulls straight out. You could probably take the car to the dealership and have them look at this real quick and see if there is significant leakage. Good Luck

BrianX54.4is · #7 07-11-2009, 07:27 PM

Measuring gas pressure alone is not a reliable method of determining if there is the correct amount of refrigerant in the system. The only sure way to know for sure is to remove the refrigerant using a recovery unit and weighing it. Then weigh in the specified amount of gas. A fridge tech/specialist can do this.

The aux fan is not going to affect the A/C performance much.

If the A/C is giving some cooling (rather than none) then the compressor is running and the problem is more likely undercharge of gas. Refrigerant can leak from the compressor shaft seal if the A/C is under-used. The compressor lube oil mixes with the gas and also coats the seal when the compressor is running. If the A/C is not used for long periods - the seals dry of oil and can leak gas. Leaks can also occur at any of the pipework connections. The fact that you noticed some improvement after adding some gas suggests that the gas charge is the issue.

Check also that the condenser coil is not fouled with dirt.

anerbe · #8 07-14-2009, 03:27 PM

^ right

Go to a shop with a proper recovery system to measure your refrigerant levels.

The Aux fan will affect idle performance noticably (see other thread about this), but if it's bad in all conditions, it could be a bad part in any section of the A/C loop. Check obvious first (condenser), and move inwards (to evap).

At this point, it may be beneficial to go to a shop who can help diagnose A/C performance.