Air con not working!

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wildeboy
Joined: Sat 18 Jun, 2011 19:54
Posts: 149

  Z3 roadster 2.8
Location: Leeds

Air con not working!

Post by wildeboy »

Ok, I know air con is not essential on a roadster but I've got it and I want it to work (but it doesn't)!

The aircon wasn't working when I bought the car, the aux fan switched on but no cold air, I had it evacuated, leak checked and recharged at Kwikfit and it worked perfectly, lovely cold air on those couple of very hot but very rainy days at the end of summer last year.

I didn't use the car much over winter but in early spring I thought I ought to run the AC to keep it all lubricated so I switched it on and no cold air! I could see the aux fan wasn't running but the weather wasn't up to me looking closely at wiring so I left it alone.

Now the weather is better I have started to have a good look at it, but I can't work out what might be wrong. There is no power to the aux fan at all, I have pulled the connector out and checked the voltage and nothing. I have looked at the high speed, low speed and compressor relays and they are all looking ok. The fuses are not blown (F16, 20, 39 and 40) but I have checked the voltage across the fuses and 16 and 20 appear ok but there is no voltage across 39 and 40. I have looked on the BMW wiring troubleshooting diagrams and it says 39 and 40 should be 'Hot at All Times' but they are not hot ever, either in accy or run or with the ac button switched on.

Does anyone have any ideas? I am not sure whether the compressor is cutting in or not, the engine does rev slightly higher when the ac switch is on.
1997 Z3 2.8 in Montreal Blue, only 130k on the clock!
OEM Roll Hoops
M50B25 Inlet manifold
BMC CDA Induction kit
Beige roof
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Heath
Joined: Tue 20 Dec, 2011 23:35
Posts: 112

  Z3 roadster 2.0
Location: Burton on Trent

Air con not working!

Post by Heath »

First of all I would check that it hasn't leaked any gas, if the gas is low it wont let the aircon switch on
If you watch the pump whilst someone else presses the switch you will see the pump start spinning. Also when you switch the aircon on you can hear it click under the bonnet & the sound of the engine changes as the aircon pump runs


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wildeboy
Joined: Sat 18 Jun, 2011 19:54
Posts: 149

  Z3 roadster 2.8
Location: Leeds

Re: Air con not working!

Post by wildeboy »

Hi Heath,

Thanks for the reply, I can hear a very slight change in engine note but can't see the compressor starting, but that doesn't really surprise me as there is no voltage across the fuse 39 which powers the magnetic lock on the compressor.

I've studied the BMW wiring diagrams looking for a reason, any reason other than low pressure! The only other thing I can come up with is faulty pressure switch!

It looks like I am resigned to having no air con, I can't justify spending £50 to have it recharged again, nevermind paying to have a leak located an fixed on top. I think I only used the air con twice last year after I had it recharged, £25 a blow is not good value in my books!!!! :shock:
1997 Z3 2.8 in Montreal Blue, only 130k on the clock!
OEM Roll Hoops
M50B25 Inlet manifold
BMC CDA Induction kit
Beige roof
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wildeboy
Joined: Sat 18 Jun, 2011 19:54
Posts: 149

  Z3 roadster 2.8
Location: Leeds

Re: Air con not working!

Post by wildeboy »

Is there a way of checking the pressure in the air con stsyem? Just to be sure it is leaking before I give up?
1997 Z3 2.8 in Montreal Blue, only 130k on the clock!
OEM Roll Hoops
M50B25 Inlet manifold
BMC CDA Induction kit
Beige roof
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Heath
Joined: Tue 20 Dec, 2011 23:35
Posts: 112

  Z3 roadster 2.0
Location: Burton on Trent

Air con not working!

Post by Heath »

I am not sure but I would have thought somewhere like kwik fit can check it with their machines, I would think that could be checked for free or very little cost


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muppet
Joined: Wed 08 Feb, 2006 17:16
Posts: 1841

  Z4 sDrive20i M Sport
Location: Roof down getting a tan

Re: Air con not working!

Post by muppet »

You really have to turn on the air con about once a meek to keep pressure in the system... so I was told by a man who seemed to know what he was talking about :?
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I have been diagnosed with ADHOTS. Attention Deficit Hyperactive Ohh That's Shiney
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Jonttt
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Joined: Sun 28 Dec, 2008 16:32
Posts: 6554

  M roadster S54
Location: Liverpool

Re: Air con not working!

Post by Jonttt »

I turn mine on about once a year and it works fine :D

I know there is the principle that you should run it regularly to lubricate the system but I'm never seen anything definative stating how often. Once a year does not seem to cause me any problems. I had it on yesturday for about 30 min as I was stuck in heavy traffic in full sun and it was ice cold and must be 12 months since I last had it on.
Happiness is not around the corner........happiness is the corner
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paulb1976

  

Re: Air con not working!

Post by paulb1976 »

just had my aircon regassed last week lovely and cold now. Anyway spoke to the guy who did mine and he said that he very rarely sees BM's with condenser or pump problems and the cost of hoses isn't that bad. It cost me £48 for a regas and pressure/leak test, the problem with KwikFit is they just plug it in and leave it and the machine tells them if there's a problem. You need an air con specialist if it's losing pressure as Kwik fit will cost you a fortune fiddling with it.

Years ago I used a mobile aircon to regas and fix a leak, cost was reasonable just over £100 from what I can remember for a regas and new couple rubber o-rings. As others have said the gas has lubricant in it as well and you'll probably find a couple of o-rings have dried out. Could be a cheap fix ???

Hope you get it sorted.
Mike Fishwick
Joined: Fri 19 Jun, 2009 10:27
Posts: 2093

  Z3 roadster 2.8
Location: Daglan, France

Re: Air con not working!

Post by Mike Fishwick »

A proper air con service will pump the old gas into a storage cylinder (being a CFC it is forbidden to discharge to atmosphere). The gas system is then evacuated to remove any moisture, and the vacuum held for 20 minutes or so to check there are no leaks from atmosphere, as these would allow moisture to enter the system, and/or lose refrigerant, depending on the location of the leak. If there is any moisture in the system the usual result is that the expansion valve (which feeds liquid refigerant gas to the evaporator) will freeze up, so stopping any gas from being discharged. The gas filter/drier cartridge would also be replaced, and the system checked when for small gas leaks while under pressure.

If all QuickFit did was do re-gas the system, it is anyone's guess what the state of the system is.

Also remember that the system will not operate at an amient temperature of less than 4 degrees C.

I would find a specialist mobile aircon man.

As for only using the aircon once a year - try using it with the heater, so producing dry warm air which will demist without turning the car into a mobile sauna! It is also great for giving instant demisting - such as if the roof has been raised after driving in the rain for a while. Living in an area which is either very hot or very cold, I use mine for most of the year, as it provides a bubble of cool air inside the car, which is great when the temperature is about 40 degrees during summer, and cool demisting in winter.

It's not a case of aircon or heating, but aircon AND heating - aircon is the best option you can have on a car, particularly a small open car such as a Z3.
A Z3 is not just for Christmas - it's for life!
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TitanTim
Joined: Mon 23 Jun, 2008 18:56
Posts: 5488

  Z3 roadster 1.9i
Location: Stafford

Re: Air con not working!

Post by TitanTim »

Have to say every car I've had which has got AC I run it all the time as useful in winter too.

Wished the Z3 had it though as stuck in traffic on Friday I was frying 8-) literally.

Tim.
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2001 Z3 1.9 Roadster Sport - 2012 Z4 sDrive 2.0 M Sport
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wildeboy
Joined: Sat 18 Jun, 2011 19:54
Posts: 149

  Z3 roadster 2.8
Location: Leeds

Re: Air con not working!

Post by wildeboy »

I am going to give Bankside in Leeds a call tommorrow, I have used them a couple of times in the past and I think there are a couple of other people on here who use them.

They say on their website they do air con repairs. Other than that does anyone know any reliable (and cheap) air con engineers in W Yorks?
1997 Z3 2.8 in Montreal Blue, only 130k on the clock!
OEM Roll Hoops
M50B25 Inlet manifold
BMC CDA Induction kit
Beige roof
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