Page 1 of 3

Hot air from vents

Posted: Mon Oct 07, 2019 8:32 pm
by Andy Collings
Hi,
My X5 E70 4.8 M Sport has a problem which isn't replicated exactly on any forums or posts that I can find. After the car has been driven for a while and then sat at idle or car driven, sat for a while and driven again the air coming out of the vents is warm to hot even with the temp dialled down to 16. Really annoying coz I bake unless I shut the vents. Has done this since I bought it in April. Have checked the manual and tried different settings but it stays hot. Had aircon regassed and serviced little while ago with no faults.
Any one got any idea's ? Thanks.
Andy

Re: Hot air from vents

Posted: Tue Oct 08, 2019 8:14 am
by StuBeeDoo
Is this not controlled through iDrive on the E70/E71??

Re: Hot air from vents

Posted: Wed Oct 09, 2019 7:15 am
by Andy Collings
Hi,
Yes it can be controlled by the I Drive or manually but the fault is there whichever selected. Doesn't always happen.

Re: Hot air from vents

Posted: Mon Feb 10, 2020 2:11 pm
by rehan
Hi,

I have an 07 4.8i.

Had similar symptoms to you after the engine heated up. It was related to an engine-to-firewall cover that had disintegrated. This was allowing the hot ambient air from the v8 engine into the area where the pollen filters are. I would get round it by turning the aircon on to cool the hot air coming in. Might be the same issue as yours so it's worth checking. I fixed it by buying the parts needed to replace the plastics that had degraded over time. Let me know if you're still having this issue.

Another issue I had was that the heating valve was sticking. Symptoms here was that the heating wouldn't get very hot, or it wouldn't get very cold. Took the valve out and found that the rubber inside them had perished. Replaced it, and it's fixed the problem.

Hope this helps!

Re: Hot air from vents

Posted: Mon Feb 10, 2020 3:24 pm
by Andy Collings
Hi,
thanks for taking time out to reply ! almost gave up after no one replied. I will check over the items you suggested and see what I find. Typical it's winter now and I haven't noticed it doing it. Will feed back what I find. Thank you!

Re: Hot air from vents

Posted: Tue Feb 11, 2020 7:18 am
by marti
Sounds to me like the heater valves are playing up?

Re: Hot air from vents

Posted: Tue Feb 11, 2020 7:32 am
by Andy Collings
I think that is the most likely culprit , will see if it's still doing it or may just change it for a new / preowned one anyway. Was roasting in the summer. Thank you for reply.

Re: Hot air from vents

Posted: Tue Feb 11, 2020 4:00 pm
by henrym3
If you have a decent code reader with live data then you can watch them open and close as you adjust the temperature. Have you checked the heater valve plug connection, perhaps put some contact cleaner on it. Personal experience is that Foxwell and INPA will show them opening and closing but I’m sure there are other scanners that will do this.

Re: Hot air from vents

Posted: Tue Feb 11, 2020 7:23 pm
by Andy Collings
Hi,
thanks for reply, have a diagnostics but not a live scanner. Have checked a couple of forum threads and most likely cause is bad Heater control valve contacts or the valve itself. Found a valve for £20.00 including pipes, will fit it when summer comes and it plays up again. Glad it's not blowing hot all the time but at the same time a bit annoying too ! Makes diagnosis hard. Thank you!

Re: Hot air from vents

Posted: Wed Feb 12, 2020 9:23 am
by rehan
Hi,

I've found some pictures of what I did when sorting this out. Apologies if the pics aren't in the right order! First is the insides of the heater valve. The rubber had completely perished, resulting in the valves not actuating properly and water not diverting to the right place! Symptoms would be that the heater sometimes would work, and if it did it was lukewarm, and it would never feel like outside cool air coming in. It's a pain to change, as it's located between the engine and wheel arch. Need small hands/long arms to do this! :)

Other pics show the engine-to-firewall plastic baffle thing (not sure of the right term here!). You can see the before and after pics. The before pics show that there's a gap below the pollen filter inlet. Hot air from the engine bay was getting past this and into the inlet for the aircon. The after pic shows that the new baffle is complete which means that air for the aircon is coming from the windscreen area. Symptoms would be a lot more apparent in the hot weather, and especially so if the car has been sitting in traffic, with hot air coming in, despite temp set to 16 degrees. I'd need to turn the aircon on to compensate. This was after the heater valve repair was done. Now, I get ambient air temperature coming in if I need to.

Just for when you next take a look under the hood.

Re: Hot air from vents

Posted: Wed Feb 12, 2020 8:25 pm
by Andy Collings
Brilliant reply, thank you so much for your time and effort, symptoms pretty similar if not exactly same as mine, baking in the summer. Went on ebay and found a valve including the pipes from a newer car but same part number. Asked the seller a few questions and advice and he came up with various idea's not all pointing to me buying his heater control valve, great service. Checked a few more threads and figured the valve was best option so bought it, will get it fitted soon. You've convinced me right decision. Thankyou! Will post updates soonest.

Re: Hot air from vents

Posted: Sun Feb 23, 2020 11:03 am
by Andy Collings
Hi Rehan,
Had a look at my baffle, it was in 3 pieces and some bits missing, was in a right state. Is the baffle just the long thin Zig Zag rubber / plastic piece that goes along the top of the tray or the whole thing including the perforated covers etc ?Where did you get the replacement parts from and how much were they? Another symptom I have which I presume is related is every now and again the engine smell coming in through vents. Appreciate any feed back.

Re: Hot air from vents

Posted: Wed Feb 26, 2020 2:49 pm
by rehan
Hiya,

I got the bits off ebay, shipped from hong kong! Not sure of the exact listing, but I searched and found these which should be suitable, hopefully the link works. Quality of which seemed to be as good as original.

https://www.ebay.co.uk/itm/3PCS-Engine- ... SwRJZdST3t

Changing them isn't too bad, took me an hour or so. If the middle bit it broken, you might need to remove the metal brace thingy (you'll know what I mean). I didn't need to change the perforated parts on mine.

On mine, there was a rubber gasket that I needed to change, if you don't have yours anymore, you will need to get one. I think I ordered a new one. Item 21 is the part here: https://www.realoem.com/bmw/enUS/showpa ... Id=41_1747 - best bet is to search for this part number online and get it a little cheaper than what BMW sell a bit of rubber for.

Also had to use some draughtproofing tape along the bottom side as the replacement came with none attached.

Once it is done, it makes a massive difference, as you no longer have air that passes through the engine bay, and into the cabin. This could result in hot air, or other smelly engine smells lol. All air now coming in is fresh air.

I feel your pain on spending too much money on this beast. I was tempted to sell it, but now that I've spent quite a bit on it, I would be losing too much in a short period of time... until the next issue arises (which might just be a phantom slow coolant leak)...

Re: Hot air from vents

Posted: Wed Feb 26, 2020 3:05 pm
by Andy Collings
Thank you very much for reply and all the information, very grateful. The link did work, I will order a set from them. I have the rubber gasket thing and it seems in ok condition. Soon as they arrive I will fit and hopefully with these and the Heater control valve change all will be good. Will get some draught proofing tape too. Does it go all the way along the bottom of all 3 pieces ? Any recommendation for the tape? Thanks!

Re: Hot air from vents

Posted: Wed Feb 26, 2020 3:17 pm
by rehan
It'll be apparent where it's needed when the old parts are taken off. It shouldn't be more than a metre or so of it if the replacement doesn't come with it attached.. I had some spare in my garage from years ago, so I don't have a link. Something that might work is this: https://www.ebay.co.uk/itm/BLACK-Draugh ... l0_C3O3RkQ