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Hot air from vents

Discuss the problems with your BMW X5 (E70).
Andy Collings
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Re: Hot air from vents

Post by Andy Collings » Thu Jul 30, 2020 6:02 am

Thank you for the post, will check the pressure when kit turns up and if ok will do a voltage check at pressure switch and short it out as required to see if it is that. As you rightly say don't want to try and run it on empty. Will update as happens.

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Re: Hot air from vents

Post by Andy Collings » Sat Aug 01, 2020 3:27 pm

Ok, all the kit turned up, the pipe and pressure gauge, the leak stop can, which is a top recommended one and doesn't clog up system, just lubricates seals etc, doesn't get affected by any water in system. Also got a top can of gas.
Checked the low pressure port and read zero on gauge, system was topped up and pressure checked last summer so can only assume that because I haven't been using air con regularly it had dried up seals and leaked out. Used the leak stop can as instructed and the pressure with engine and ac on max was just over 20 psi. Stopped the engine and gauge went up to about 50 psi. kept eye on gauge for a while and pressure held with engine off. As the pressure was still slightly low as per forum reviews I added the spare can of gas, ran engine again for recommended 10 mins with ac on full blast. Stopped engine and gauge now at about 40 psi. Disconnected the test gauge and ran the ac again, lovely, lovely cold air came out, was well chuffed.
Next put the diagnostics on and checked my previous 2 codes E723 and E729, the E729 had gone so pressure switch is all good and ac wasn't working due to the failsafe of the pressure switch sensing no pressure. Next replaced the condensation sensor, an easy job, diagnostic said this was faulty. Hey presto, fault cleared and not returned. Stopped playing with car at this point as thought luck was going to run out. Still got some issues but for another day. Will keep an eye on ac pressure over next couple of weeks and see how it goes, will get a couple of top up cans in case for the future.
Thank you for all the advice about this problem and others, info has been invaluable and has no doubt saved me a lot of money.
Andy

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Re: Hot air from vents

Post by X5Sport » Sat Aug 01, 2020 6:31 pm

I’m sorry that I assumed your ac was actually working but no temp control so forgot to say a lot earlier about checking the gas level :oops:

It should not lose it in a year though and that would tend to indicate perhaps a slow leak somewhere. You’ll need a dye tracer to find it though - best left to the pros I think - and a UV light.

Glad you’re getting somewhere with it at last :D Rumour has it there’s a heat wave on the way.
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Re: Hot air from vents

Post by Andy Collings » Sun Aug 02, 2020 10:41 am

Finally got round to fitting the draught excluder to the bulk head plastic trim. Car going in garage end of month for some other stuff, so will get them to fit them, will give them the remaining excluder to fit where they think required.

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Re: Hot air from vents

Post by rehan » Mon Aug 03, 2020 11:05 am

Glad your aircon is sorted! A sign of the aircon losing pressure is that the driver side vents will be slightly warmer than the passenger side. Mine seems to deplete over the period of a year, so I will also need to keep an eye on it. I can hear a slight whining sound whenever the compressor is engaged, so perhaps that is on it's way out (for me). Best of luck with the baffles, it should complete your journey to climate control goodness!

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Re: Hot air from vents

Post by Andy Collings » Mon Aug 03, 2020 4:45 pm

Thanks for the post, after a couple of days and still nice and cold. Will keep checking pressure and see how we go. Some owners say they have to top up every 6 months. Have you tried the leak stuff? Nice weather coming so so glad I sorted it, fingers crossed.

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Re: Hot air from vents

Post by Andy Collings » Sun Aug 09, 2020 7:53 pm

Been a few days now since top up etc, been away for weekend and it's been roasting hot. Done 300 miles with air con on and just got home. Checked pressure with the purchased gauge, engine off is 95 psi and engine running air con on full is 45 psi. All appears fine and ice cold, noticed though that with air con on it does affect the engine revs. When slowing down for traffic lights, junctions etc in the lower gears the revs increase, have to be careful because it wants to slightly accelerate when I want to slow down, could be dodgy. Only does it with air con on. Anyone had the same experience?

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Re: Hot air from vents

Post by X5Sport » Sun Aug 09, 2020 9:18 pm

Definitely not. It doesn’t on any of our BMWs. Engines are N57S (E71 40d twin turbo), B47D twin turbo (F46 20d) and M57TU (E46 330d). Ok the first two are 8sp autos but the last one is a manual and the revs don’t change regardless of the ac on any of them. My X6 has 4-zone climate and the F46 has two-zone climate.

The only thing that I can think of is that is is so blooming hot (worse south of London) that maybe there’s extra load being caused as the ac compressor is having to work harder? That’s pure guesswork though.
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Re: Hot air from vents

Post by Andy Collings » Mon Aug 10, 2020 7:58 am

Hmmm, will keep an eye on it then. Thought it was weird and also dangerous, if I wasn't prepared for it I could easily have bumped any car in front or anything else in front. Will search the forums and also contact BMW. Can't be right. Will post any update. Def only does it with air con on and you right it was very hot.

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Re: Hot air from vents

Post by Andy Collings » Mon Aug 10, 2020 10:59 am

Read forums etc, unusually it is normal for some X5's to do this. It's engineered to do it, apparently it's due to the extra load on engine and stops it stalling. Dealer confirmed it.

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Re: Hot air from vents

Post by X5Sport » Mon Aug 10, 2020 11:03 am

Interesting, and another useful factoid for the forum. Definitely one to watch out for, especially if not used to it and not expecting it. I know anti stall kicks in under electrical load but it doing it on the ac as well is one to be very mindful of.
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Re: Hot air from vents

Post by Andy Collings » Wed Aug 26, 2020 7:17 pm

Quick update, Air con still all good. Fitted the bulkhead bits x3 at last with draught excluder. All looks much better, time will tell about the smells etc.
As a note, just changed all 4 tyres for Accelera Iota ST68's, read a few forums of different car makes and unbiased reviews, this model in particular seems very good. Bought all 4 from Ebay supplier Brand new for princely sum of £312.00. I think a bargain, will give some feedback on my opinion after some trips and different weather conditions. Original tyres had an advisory on MOT for wear on inner edge of both rears. Will get a 4 wheel alignment done next week and accurately keep eye on tyre pressures.

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