Smoke/Burning smell in the cabin - 63 Plate A4 2.0 TDie SE Teknik - A/C maybe

[banquo]

Just wondering if I did the right thing buying my ex Company Car on retirement....
It's got 40,000 miles on the clock, and has been trouble free until now.
Set off for the shops tonight and half a mile from the house encountered a strong smell of burning.
Thinking it was outside, I wound the windows down, but it got worse, and I realised that the cabin was filling up with smoke.
Pulled in and stopped and lifted the bonnet; nothing noticeable under there although it was pitch dark.
Only thing I can think of is something to do with the A/C. It's freezing up here, and having lost my scraper since last winter, I'd had the screen demister on for a while to clear the ice, and that switches the A/C on. I don't use the A/C much, so I wondered if it could have seized up or something?
Burning smell a bit like burnt clutch or brake smell. I did wonder if the belt might be slipping (assume it has a belt) but there was no screeching noise.
Is there anything that's easy to check to find out what might be wrong?
Last time I worked on cars was when they had carburettors and drum brakes, so I'm a bit out of touch...:o
Thanks in advance!

[Boy]

Does the story continue or did you leave the car there and retreat?
When did you last have the a/c on?
I think if the a/c was causing smoke in the cabin, you would have detected it also under the hood.
Presumably no warning lights or other alarms?
I hope this story has a happy ending. Please keep us posted

[Rob69]

Does everything still work? fan speed control, flap position controls etc. check the air con compressor pulley and belt in daylight. I also think your car has an electric auxiliary heater alongside the usual heater matrix to boost demisting, check to see if this is fitted and still working, should be a large fuse for it somewhere!. It might just have been covered in dust and been burning off that if not used for a while.

[banquo]

Does the story continue or did you leave the car there and retreat?
When did you last have the a/c on?
I think if the a/c was causing smoke in the cabin, you would have detected it also under the hood.
Presumably no warning lights or other alarms?
I hope this story has a happy ending. Please keep us posted

Thanks for your reply; I stopped, opened all the windows, and had switched off the screen de-icer (mainly so I could try and hear if anything was happening). Carried on with journey with no further use of rapid de-icer) and no further smoke, although the inside of the car was stinking of it, so hard to be sure that nothing at all was coming through. No warning lights, etc. Everything else seemed fine.

[banquo]

Does everything still work? fan speed control, flap position controls etc. check the air con compressor pulley and belt in daylight. I also think your car has an electric auxiliary heater alongside the usual heater matrix to boost demisting, check to see if this is fitted and still working, should be a large fuse for it somewhere!. It might just have been covered in dust and been burning off that if not used for a while.
Thanks for your reply; I'll take a look now that the sun's thinking of coming up. Fan settings worked fine. I didn't try any other flap settings, but will check today. Not aware of an auxiliary heater, and given the time it takes to de-ice suspect that I don't have one. I'll take a look at the fusebox.

[Rob69]

There are diesel fired webasto auxilliary heaters fitted to some cars to aid engine warm up, but others have direct electric heating in the cabin air duct, here's a bit waffle, sure you can find more, but I suspect you car car has the electric heating boost. Discussion is getting heated | Diesel Car Magazine (http://www.dieselcar.com/features/doctor/discussion-is-getting-heated/)
Maybe you had dirt on the element, a bit like getting fluff pulled into a hairdrier and burning off. hopefully something simple like that anyway

[banquo]

Not much to to look at it today unfortunately. No sign of damage to the belt drive and it's so far away from the air intake, I can't see it being that. I noticed a pile of leaves below the cover for the air intake, just in front of the screen, so it would be easy for something to get sucked in there perhaps, but the smell definitely wasn't burning eaves. Maybe I've got a dead mouse in there... Pulled the cover and hoovered all the stuff out, noting a nice little rust trap between the bonnet hinge support and the inner wing, that was full of wet mud on both sides. Also managed to lose one of the plastic screws that holds the cover down, so if anyone knows the part number for those, that would be useful. Idiot...:mad: It's a large plastic Quick-Fit screw, with a large diameter head of about 20-25mm and a screwdriver slot.
On the plus side, the car ran fine for a 60 mile round trip, all fan settings work, and the vane settings all work. Still stinks inside though.
I've been in the manual and an auxiliary heater fuse is mentioned; still need to pull the fuse cover, and see if I have a fuse for that, to demonstrate that there's supposed to be one.
If there is, might just take a chance and try switching it on again, to see what happens. Maybe with a fire extinguisher to hand...
Thanks for all the help so far

[Boy]

Glad to hear that all seems reasonably well. In your position, as well as checking the fuse etc., I would pull out the cabin air filter and see what state that is in. it is a two minute job, above the passenger footwell and if there was so much crxp under the cover of the plenum chamber, there is reasonable chance that some made it to the cabin filter.

[Rob69]

Are the screws like these? dealer or TPS might be best just for one screw though
10 x AUDI VW VOLKSWAGEN Bumper Trim Protection Screw Spoiler Dowel Pin | eBay (https://www.ebay.co.uk/itm/10-x-AUDI-VW-VOLKSWAGEN-Bumper-Trim-Protection-Screw-Spoiler-Dowel-Pin/222164535289?fits=Car+Make%3AAudi&hash=item33ba09c7f9:g:d5AAAOSwGIRXbRp8)

[banquo]

Glad to hear that all seems reasonably well. In your position, as well as checking the fuse etc., I would pull out the cabin air filter and see what state that is in. it is a two minute job, above the passenger footwell and if there was so much crxp under the cover of the plenum chamber, there is reasonable chance that some made it to the cabin filter.

Cheers Boy; I'll take a look at that; screws are similar, but not the same. I'll try the dealer

[banquo]

Not much progress with this. Turns out the Owner's Manual doesn't cater for right hand drive vehicles, and the fuses they say are on the right side of the dash are actually on the left, and vice versa. I'd seen some substantial fuses under the right panel, where the 'supplementary heater' fuse was supposed to be, but it's actually on the left and rated at only 5A, so less than 60W, which would be useless. When you think of it, why would anyone fit an electric heater to a car with aircon? When I was at work, we had aircon in the office, and it worked in reverse in the winter, heating the air istead of cooling it. My guess is that's why the aircon comes on automatically when you select the de-icing function. There's certainly no substantial fuse, and if an auxiliary heater were to be fitted, I'm guessing it would require at least 50-60 amps for any worthwhile benefit, and that would require a relay with circuit breaker rather than a fuse.
You can see the level of debris under the cover, but not much had got through to the filter, although as it's not long since it was serviced (cheaply, by the lease company's choice, and not at a dealer), I suspect they didn't bother replacing it. I just knocked the dirt off it and stuck it back in. It's grey ln both sides, so I'm assuming that's charcoal impregnation, and not dirt...
https://farm5.staticflickr.com/4555/37936858304_46f29bbcae_b.jpg (https://flic.kr/p/ZNmjgS)leaves (https://flic.kr/p/ZNmjgS) by bancquo (https://www.flickr.com/photos/17279292@N03/), on Flickr
https://farm5.staticflickr.com/4559/37936858244_d9f7ccf69e_b.jpg (https://flic.kr/p/ZNmjfQ)leaves2 (https://flic.kr/p/ZNmjfQ) by bancquo (https://www.flickr.com/photos/17279292@N03/), on Flickr
https://farm5.staticflickr.com/4543/37958604874_ffd4f44ff1_b.jpg (https://flic.kr/p/ZQgLLJ)cabin filter (https://flic.kr/p/ZQgLLJ) by bancquo (https://www.flickr.com/photos/17279292@N03/), on Flickr
For future reference for anyone who needs one, it's a Mann CU 2450
https://farm5.staticflickr.com/4548/37958604724_a3bee7733b_z.jpg (https://flic.kr/p/ZQgLJ9)Mann CU2450 (https://flic.kr/p/ZQgLJ9) by bancquo (https://www.flickr.com/photos/17279292@N03/), on Flickr


Think I'm just going to have to bite the bullet and try switching the de-icer back on, and see what happens (or never use it again would be another option)
Really appreciate everyones' help so far.

[The Technician]

The filter shown should be white, that looks like it has never been replaced?

[banquo]

No. I don't think kit has, although I don't know what the service intervals are for it.
Car has done 40,000 miles and has had two services.
Either way, it's not the cause of the smoke...

[Rob69]

That's a pretty choked up plenum !! the cabin filter is also dirty, really poor quality servicing if they don't change the pollen filter on a two yearly service and you say the car has just recently been in for a service - it should be white when new, as said by the technician. you need to clean that plenum to avoid the water drains getting blocked and flooding the plenum, also suggest you go to annual 10k services if you intend to keep the car.
Not saying your car definitely has an electric heater but here's on on fleabay as example, the idea is it gives you almost instant heat to the screen instead of waiting for engine coolant to warm up, AC come on to dehumidify the air going to the screen to demist the screen quicker than blowing saturated air onto the screen, it doesn't act as a heat pump as you describe was used in the office.
AUDI A5 8T / A4 B8 ELECTRIC AUXILIARY HEATER MATRIX ELEMENT 8K0819011 | eBay (https://www.ebay.co.uk/itm/AUDI-A5-8T-A4-B8-ELECTRIC-AUXILIARY-HEATER-MATRIX-ELEMENT-8K0819011-/391549528738)

[Whippy53]

Dpf??

[banquo]

Thanks for that Rob; I'm wondering if that heater comes with an optional winter pack; I seem to remember (it was four years ago though) that there was an option for that, but don't quote me. Not sure how else to find out if it has one...
I already hoovered out the area under the cover (that's why I had the cover off) and hosed it down to make sure it's draining OK. I see I can get a pattern cabin filter for under a tenner on eBay, and even the Mann one isn't too dear.
The car was supplied by Days Contract Hire, and hasn't been near a dealer except for a recall. They used a Bosch Service Centre, and I doubt they did much to it except the bare minimum. Cheapskates. Thanks for the info on the aircon; not often I'm right, but looks like I'm wrong again... :Blush2:

[Rob69]

I'd say as a quick check to see if you have one and it still works start up the car on a cold morning and switch on the demister setting and see if you get heat through in a few seconds rather than minutes. I'm not familiar with your car as I exist several years further down the food chain carwise (2005 passat) but maybe you have some sort of display showing heater settings or maybe its described in your handbook.

[banquo]

Thanks Rob; I'm busy trawling the handbook and Google, but no luck so far. I've used the de-icer in the winter for the past 4 years, and it does take a while to work, but that's not to say it wouldn't take longer if it didn't have an extra heater, so that's not much help unless we know for certain. There's just one button for the de-icer. It lights up, the aircon comes on, and the fan starts slow, and speeds up as the air warms up. I'll keep you posted, and thanks again.

[Grambrow]

Suggest you check for any codes.
I had a cable harness inside the door short circuit, which was melting the wire insulation and smouldering, which showed up as multiple codes. This was caused by the window glass continually falling on to the harness and damaging the insulation. I put this down to my fault when I had replaced the window regulator and probably failed to correctly relocate the loom. Unlikely to be your problem, unless you have had any door work done lately!



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[banquo]

No work done, apart from a minor dent removal on the lower front sill, behind the wheel arch, and certainly nothing going on in the doors.
How do you check for codes?

[Rob69]

you need to find someone with VCDS or get a garage to hook it up to a decent code reader, not just generic OBDII reader as these won't pick up all modules in the car.

[Boy]

As Rob says, VCDS is the scanning tool to use. If you showed your location we might know if we could usefully offer to scan for you.
I am guessing from your name that you might be in Angus or thereabouts but if you are further West, I shall be up there for Christmas.

[banquo]

Thanks for the offer; Perth, and no, it's not in Australia...:aargh4:

[Boy]

Ok, probably we shall not be near Perth. Suggest you look elsewhere on this forum for a local vcds member. Good luck.

[banquo]

Ok, probably we shall not be near Perth. Suggest you look elsewhere on this forum for a local vcds member. Good luck.
Nae bother mate; the offer was appreciated

[banquo]

Never did get to the bottom of this, and despite trying the rapid deicer several times, no more smoke. However, yesterday, what should drop through my door but a recall letter from Audi advising of smouldering from the auxilliary heater:

https://farm5.staticflickr.com/4772/38901038720_9e07f63299_h.jpg (https://flic.kr/p/22gxZw9)Audi recall noname (https://flic.kr/p/22gxZw9) by bancquo (https://www.flickr.com/photos/17279292@N03/), on Flickr

[Rob69]

Thought I recognized this thread - result in your favour then !!

[banquo]

Looks like it; the service guy was really excited when he heard of my smoke event. They've done about 50 already, and not found anything. As far as i can make out, the issue is with insulation breakdown, resulting in a short and a possible fire.

[Rob69]

See if you can get a photo of the element that is removed, it might help others here.

[banquo]

I'll ask, but I don't see them giving a positive answer....

[Boy]

My 2013 TDI has been recalled for this also but I had no burning smells yet.
Has your car yet been attended to? I am a little worried that the eater might be made less affective.

[banquo]

It's going in next Monday; I used the car menu to disable the heater, but actually, I think it's burnt out, and I haven't noticed any difference. I suspect the burning smell was the heater burning out.

[Boy]

Thanks. Please let us know how things go and whether there is any difference after the mod.

[banquo]

Will do

[banquo]

Well, I don't get the old heater away with me, but I do get an AudiCam video (https://audicam.audi.co.uk/customer/1909500/169244427f2ab1da3f6446c6c141b7f7/263214) of the work, and the burnt out heater element. Not sure how long the link works for, but assume it will expire at some point.

[b8sline]

Got the same letter through the door the other day, no smell either.