E39 air con

[SJobson]

Now the sun has finally come out, I've remembered that my E39's air conditioning doesn't appear to come on straight away. Last night I had to wait with the engine running for a minute or two before cool air started to be blown from the vents; I didn't have to do anything with the climate settings, though, so I guess the sensors are working properly.

Is it normal for an E39's air-con to take a minute to turn on?

[Neil.D]

Yes it isnt instant as it has to kick start the compressor which is belt driven. As long as it wourks then all should be fine.
Remember to use it during the winter as lack of use causes the pipes to dry out, crack and leak the fluid out.

[Pickled Piper]

If it's on Auto and set to a low temp, then you should hear the fan quite clearly running at high speed as soon as you get into a hot car. Cold air should follow soon after.

pp

[SJobson]

It is indeed used all year, never off except when it won't work due to the low outside temperature.
Not sure about the fan noise? The ventilation fan turns on instantly when I turn on the ignition after it's been in the sun. The compressor is inaudible over that, so I can't tell exactly when it kicks in. It clearly does because it's cooling the air after a little wait.
Every other car I've owned with climate or air con starts to chuck out cool air almost immediately, though. The E39 blows air but takes a minute to blow it cold. I'll probably get the gas checked when I next visit my indie, but I did wonder whether they all do that, sir.

[madou]

SJobson said:

Is it normal for an E39's air-con to take a minute to turn on?

Mine reaches the target quickly, and does speed up if it is far from the target. One of the few parts I haven't had replaced yet

[SJobson]

Oddly it was quicker last night when I got in the car. Might be something to do with how the central air vent is set - I didn't have it on maximum cold when I noticed it was slow to cool down.

[Bill Carr]

My old E39 535 used to do exactly the same thing. It would take about a minute to get cold, blowing warm air until then. Then it would blow cold. I assumed that it was either the air-con gas was on its way out or that the system took a little while to spool-up.

[williamp]

One other thing. I remember the E39 having somehting behind the dashboard which stores engine heat. Throughout winter, I could never get this to work. The only heat would appear after a few miles of driving, regardless of the engine settings. Also, I have the timer which turns the heater/cooler on before I get in. Very nice, as it cleared the windscreen but it was never hot.

[SJobson]

I think the engine heat store is only intended to work at the end of the journey, to keep the cabin warm after you've turned the engine off. The diesels could be had with a pre-heater which warmed them up before use on a timer.

Bill, that sounds exactly what I felt on Tuesday. I take it you never did anything about it?

[Bill Carr]

SJobson said:

Bill, that sounds exactly what I felt on Tuesday. I take it you never did anything about it?

Correct - after a short wait it still blew cold so I just left it. Was still like that when I got rid of the car.

Might be worth posting on http://forum.bmw5.co.uk

Edited by Bill Carr on Thursday 8th May 12:55

[welwynnick]

SJobson said:

Now the sun has finally come out, I've remembered that my E39's air conditioning doesn't appear to come on straight away. Last night I had to wait with the engine running for a minute or two before cool air started to be blown from the vents; I didn't have to do anything with the climate settings, though, so I guess the sensors are working properly.

Is it normal for an E39's air-con to take a minute to turn on?

I've just sold my E39, but the air-con always came on quickly when needed- two minutes is too long.

When was it last r-charged? The gas only stays put for three or four years even when the condensor isn't damaged. If you haven't had it charged in that time I would get down to a large Halfrods store and get an aerosol of R134a. As long as you don't have a specific fault, its strongly recommended.

Nick

[SJobson]

Cheers Nick, I think I'm noticing that it's getting to need a recharge. I've only had it a year, but it's now heading for 8 years old and I don't think I've got a receipt for a recharge. It's not actually 2 minutes, either - if I put the dash vents to fully cold (3 blue dots) then it probably only takes about 30-40 seconds to pump out chilled air in quantity.

[derin100]

Two questions I'd like to ask:

1) This getting an aerosol from Halfords thing? Does that mean you can recharge yourself?!

This would be great as I'm getting sick of my local place charging £100-quid for what seems like very little effort or materials.

2) Doesn't driving with the A/C button on all the time put fuel consumption up?

Thanks

[SJobson]

If you drive a 540 you don't care about 0.1mpg extra

However, since it's automatic climate control, I would hope that it cuts in and out as necessary rather than just being on all the time. Having said that, my previous cars with normal on/off air-con have never been appreciably more economical with it off; they're slightly more responsive (the Puma 1.7 being notably so - but then it had the least power and was lightest so you'd expect to feel the effect most in that).

Driving around without air-con on seems a pointless waste - the amount of fuel saved is negligible compared to the cost of replacing the bits that seize up through lack of use. And it's much more comfortable to have it on.

[welwynnick]

derin100 said:

Two questions I'd like to ask:

1) This getting an aerosol from Halfords thing? Does that mean you can recharge yourself?!

This would be great as I'm getting sick of my local place charging £100-quid for what seems like very little effort or materials.

2) Doesn't driving with the A/C button on all the time put fuel consumption up?

Thanks

Yes, you can re-charge yourself, and its quick and cheap and easy. If your air-con has a real fault, or hasn't been working normally for a long time, I'd still suggest a specialist with some experience, but in most cases anyone can refill themselves for £20-30.

There are two ports on every modern AC system: low-pressure (small port) and high-pressure (large port). They are generally located near the compressor, but high up and near the front of the engine compartment. It's as if the manufacturer knew that they would need regular access! Re-filling is done through the low pressure port, and fortunately you can't get them mixed up.

Connect the aerosol using the connection provided, start the engine, set the AC to full cold and press the valve. It can take a few minutes, but that's it. Some aerosols come with a pressure guage, and that can be useful. I bought a stand-alone guage, as I plan to use it many times!

recommended, Nick

[MK4 Slowride]

buffly said:

I always have the aircon switched on, and just hit the Auto button.... in hot and cold weather.

Having the 'snow flake' on all year round is bad as it's sucks a bit of performance from the car. Also fuel is compromised a bit as well. Give it a blast now & then in winter but not all the time.

[derin100]

Thanks Nick

That's really useful info!

I don't need it for my E39 daily driver but my E32 735i is decidedly wimpy in the A/C department but as I a) rarely drive the car and b) have just shelled out another large wedge of cash on cars I kind of resent the price my local place charges.

[welwynnick]

derin100 said:

Thanks Nick

That's really useful info!

I don't need it for my E39 daily driver but my E32 735i is decidedly wimpy in the A/C department but as I a) rarely drive the car and b) have just shelled out another large wedge of cash on cars I kind of resent the price my local place charges.

Ahhhh ....... you might have a problem there.

You MUST check what sort of refrigerant the 735i uses. Newer cars use R134a, but older cars use R12, which is now completely banned. It will say so on a sticker at the front of the engine compartment. If it's R12, you cannot fill with R134a under any circumstances. You would need an R12 substitute, and will need a specialist for that.

regards, Nick

[sparks87]

The air con fan in the E39 shouldn't always be on should it, only when the air con is switched on after a minute or so?

[David87M3]

No it shouldnt. the aircon pusher fan also act's as an engine cooling fan. My 528 fan use to run a lot and I discovered the bottom rad hose was almost as hot as the top hose

there's also a switch in the bottom hose that activates the fan.

You can do an instrument cluster hidden test to display real time engine temp and I discovered my engine was running at 98-110 degrees, hence the fan running. New rad and stat engine 92-94 degree's and no fan

Dave