AirCon - not cold, but compressor working?

[more_fasterer]

Hi team,

I'm hoping someone can help me pinpoint what's going on with the climate control on my 2005 3.0d. This isn't the usual low refrigerant level or failed aux fan issue, at least I don't think it is anyway. The symptoms are:
- Air from the vents is always at ambient temperature
- Interior fan operates correctly
- No faults logged by any ECU
- A/C compressor runs when A/C button is turned on
- Aux fan runs when tested in INPA, but I didn't observe it running while letting the car idle with the climate control set to "max" for ~5 minutes
- The hard line from the compressor to the condenser gets hot, nearly too hot to touch
- Both the hard lines running alongside the engine from the firewall (i.e. to and from the evaporator) are neither hot nor cold to the touch

The car has done 190,000km (120,000mi). I expect a trip to the local aircon specialist is in order, but I'd like to know if there's something I should be looking at outside of the refrigerant system. It's potentially likely that they'll find the system pressures are OK, otherwise the compressor wouldn't kick in.

Any guidance appreciated!

[andrewwynn]

Compressor will kick on with minimum pressure. If there is not enough quantity of refrigerant in the system, it can't generate a pressure differential to cause the temperature differential but also at least on some x5s, the system uses a variable orifice so there are some options of failure point.

I help maintain a bunch of cars and with only $70-80 for a manifold kit for measuring high and low pressure it paid for itself the first use. Learning the expected value and determining what the actual value is plus knowing what it is this year vs last year helps determine if it's wearing out.

I added an extra port so I can connect regular or quick connect R123a cans to mine. I also bought a $20 Venturi vacuum but ended up getting a real vacuum pump for about $80 which I traded for fixing a friend's AC. Paid for itself.

[Crowz]

Originally Posted by more_fasterer

Hi team,

I'm hoping someone can help me pinpoint what's going on with the climate control on my 2005 3.0d. This isn't the usual low refrigerant level or failed aux fan issue, at least I don't think it is anyway. The symptoms are:
- Air from the vents is always at ambient temperature
- Interior fan operates correctly
- No faults logged by any ECU
- A/C compressor runs when A/C button is turned on
- Aux fan runs when tested in INPA, but I didn't observe it running while letting the car idle with the climate control set to "max" for ~5 minutes
- The hard line from the compressor to the condenser gets hot, nearly too hot to touch
- Both the hard lines running alongside the engine from the firewall (i.e. to and from the evaporator) are neither hot nor cold to the touch

The car has done 190,000km (120,000mi). I expect a trip to the local aircon specialist is in order, but I'd like to know if there's something I should be looking at outside of the refrigerant system. It's potentially likely that they'll find the system pressures are OK, otherwise the compressor wouldn't kick in.

Any guidance appreciated!

1. Compressor running
2. Aux Fan works but not coming on.
3. Not cold
4. Attempting to add Freon but system wont take Freon and or gauges show no pressure/vacuum to speak of.

Bad compressor.

[upallnight]

Originally Posted by Crowz

1. Compressor running
2. Aux Fan works but not coming on.
3. Not cold
4. Attempting to add Freon but system wont take Freon and or gauges show no pressure/vacuum to speak of.

Bad compressor.

Do you have the variable valve compressor? Have you hooked up a set of gauges to the low and high side of the system? If not hook up a set of gauges and tell us what the low side and high side readings are.

Don't have a set of gauges or don't know how to hook up a set of gauges, pay for my round trip ticket to NZ and I'll bring my tool and I'll tell you what the pressures are. If that is too expensive for you, take it to an AC shop and let them tell you what the pressures are. If that is too expensive, just lower the windows and drive around with natural air conditioning.

[andrewwynn]

Love when there are multiple solutions. ;-)

Is there the equivalent of Harbor Freight in NZ? I'm happy with the quality of the high/low gauges I got there and it is required for actual troubleshooting.

Compressor won't kick on without minimize low side pressure

Hot on high side indicates compressor is compressing. If low side doesn't get cold, problem should be related to the orifice or the dryer.

One possibility: air in the system. Introduction of air will cause exactly the symptoms you describe

So: definitely need to know high and low pressure with compressor on and off to know the next step

[upallnight]

Originally Posted by andrewwynn

Love when there are multiple solutions. ;-)

Is there the equivalent of Harbor Freight in NZ? I'm happy with the quality of the high/low gauges I got there and it is required for actual troubleshooting.

Compressor won't kick on without minimize low side pressure

Hot on high side indicates compressor is compressing. If low side doesn't get cold, problem should be related to the orifice or the dryer.

One possibility: air in the system. Introduction of air will cause exactly the symptoms you describe

So: definitely need to know high and low pressure with compressor on and off to know the next step

It is probably the expansion valve.

Part number 64116981454 EXPANSION VALVE.

Since you probably don't have a recovery machine to recover the refrigerant that is in the system, you will need to take it in if this is the part that needs to be replaced.

[andrewwynn]

Bingo that's the exact part I was thinking of. I read that some AC systems have a variable expansion valve. If there are moving parts there is something to fail. I don't know anything about it though: is it electrical? Solinoids ? If so could be a fuse or connector or controller.

My AC wasn't working because the low side sensor wasn't completely plugged in. That was a good day when that Discovery was made.


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[andrewwynn]

It is interesting the requirement for recovering the R134a when it's the same chemical used in dust blasting cans. EPA overreach? Just seems strange. The point of switching from more effective R-22 is the lack of environmental impact. Consider that a full charge on x5 uses maybe two dust blasters worth of R134a. Doing plumbing work I've used 134a to freeze a pipe that has no valve to do repair (you can buy a kit for $50 but I made my own using an R134a can punching valve and a needle point shop air blasting gun. ) I use the same setup for dust blasting as R134a dosent have the bittering agent that makes dusters useless for dusting. (great now my keyboard has no dust but has the equivalent of pepper spray on it)


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[Crowz]

This might help some.

BMW X5 Air Conditioner Compressor | Crowz Nest

[upallnight]

If you find out that you do have a variable displacement compressor, you may be able to get by with just having the solenoid operated valve that controls the displacement of the compressor replaced.

Here's a video on that replacement procedure on a VW. This is a job that requires a shop that have the equipment to evacuate and recover the refrigerant in the system before proceeding with the repair.

https://www.youtube.com/watch?v=xMrU4XimsoI