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.

[more_fasterer]

Thanks for the advice guys. We can't buy R134a over the counter here in NZ for environmental reasons, so I'm gonna be stuck with taking the car to a service agent to get the aircon working properly.

With that said, I went to a friendly auto electrician today (to talk about an issue with the 335i... sigh, BMW life) and it turned out that he had a set of gauges. The low side was sitting at 26psi and high was at 220psi, so a bit low but not out of range. Oddly, he added a bit of gas into it and now it generates a modicum of cold air, unless the engine is idling - in which case no cooling occurs.

Originally Posted by upallnight

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.

Yes, it has a variable compressor.

Originally Posted by upallnight

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.

I feel like you could've presented those options in a slightly different order

Originally Posted by Crowz

Only issue I have with replacing the valve is that for me it didn't help any and the fact I was out the money for Freon and the valve.

Well that and it was a pain to fool with from under the car.

Factoring in the cost :

$40 crappy snap ring pliers set
$15 Freon
$15 valve
Gas to go get Freon and valve.

So $70 in parts and the royal pain of fooling with the compress from under the car.

New compressor which I had to buy anyways because the valve didn't fix it was $110 or so.

So a bit more and you have a new compressor and piece of mind.

Its just not worth it to fool with the valve. If the valves toast then the compressor isn't that far off. New compressor has new valve.

Good feedback. Thanks for the link to your useful write-up, too. I'm gonna organise to have the car looked at by an aircon specialist, cos I don't really have much option. Which kinda grates, as I have DIY'd everything else on this car (including changing the trans solenoids). But it sounds like I can expect a "you need a new compressor" diagnosis.


Cheers guys

[upallnight]

Originally Posted by more_fasterer

Thanks for the advice guys. We can't buy R134a over the counter here in NZ for environmental reasons, so I'm gonna be stuck with taking the car to a service agent to get the aircon working properly.

With that said, I went to a friendly auto electrician today (to talk about an issue with the 335i... sigh, BMW life) and it turned out that he had a set of gauges. The low side was sitting at 26psi and high was at 220psi, so a bit low but not out of range. Oddly, he added a bit of gas into it and now it generates a modicum of cold air, unless the engine is idling - in which case no cooling occurs.



Yes, it has a variable compressor.



I feel like you could've presented those options in a slightly different order




Good feedback. Thanks for the link to your useful write-up, too. I'm gonna organise to have the car looked at by an aircon specialist, cos I don't really have much option. Which kinda grates, as I have DIY'd everything else on this car (including changing the trans solenoids). But it sounds like I can expect a "you need a new compressor" diagnosis.


Cheers guys

The low side appears to be lower then the design parameter. What was the ambient air temperature when these readings were taken?

It could also be the expansion valve that is attached to the evaporator inside the car. You will need to recover the refrigerant before you can replace it.

GL

[more_fasterer]

Originally Posted by upallnight

What was the ambient air temperature when these readings were taken?

24deg C, which is mid 70's in fahrenheit.

[wpoll]

Originally Posted by more_fasterer

Thanks for the advice guys. We can't buy R134a over the counter here in NZ for environmental reasons, so I'm gonna be stuck with taking the car to a service agent to get the aircon working properly.

While this WAS true, something seems to have recently changed and we can now get R134a over the counter.

SCA now have it - CRC AC Charge Refill & Hose - 400g - Supercheap Auto

And there's an auto-cool specialist up your way that sells online...CoolKiwi.

Welcome to Coolkiwi Automotive Enhancements | YOUR FAVOURITE DIY AUTOMOTIVE PRODUCTS

My cooling performance has dropped off a little over the last year - I think I have a very slow leak. Might try one of these one day.

*edit* I see CoolKiwi also does a gauge set...

R134a 2-Valve Air Conditioning Manifold Gauge Set | Welcome to Coolkiwi Automotive Enhancements

[more_fasterer]

Originally Posted by wpoll

While this WAS true, something seems to have recently changed and we can now get R134a over the counter.

SCA now have it - CRC AC Charge Refill & Hose - 400g - Supercheap Auto

And there's an auto-cool specialist up your way that sells online...CoolKiwi.

Welcome to Coolkiwi Automotive Enhancements | YOUR FAVOURITE DIY AUTOMOTIVE PRODUCTS

My cooling performance has dropped off a little over the last year - I think I have a very slow leak. Might try one of these one day.

*edit* I see CoolKiwi also does a gauge set...

R134a 2-Valve Air Conditioning Manifold Gauge Set | Welcome to Coolkiwi Automotive Enhancements

Sweet, thanks!

[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