Smoke at idle after a run

[DaytonaSarge]

Evening all,

Been a while since my last post, hope everyone is well. Still enjoying the B7 after a few years of happy ownership (slight DRC dramas that were thankfully sorted under the "goodwill warranty" thanks to some pointers from the lads on here!)

Just wanted to see if anyone has had any issues after noticing this today. Was on a bit of a drive, about 60 miles, pulled over at a petrol station so my mate could grab a coffee, I was sat in the forecourt with the engine running an noticed that there was a bit of smoke coming from the rear. Nothing unusual as I know these muthas like a bit of a smoke from time to time, but when we eventually got away (after being sat for about five minutes) upon rejoining the carriage way "at pace" I can only confirm I left a smoke screen behind me that Bond wouldve been proud of, so much so it looked to me like people slowed down to get thru it! A little disconcerting...

I'm thinking perhaps after 60k of mileage I'm potentially looking at the results of high carbon build up in the manifold, only getting minimal smoke during start up an it runs pretty clear when mooching about, just when it's sat idling it starts to smoke pretty heavily (clearly!).

Anyone else had or noticed this? I've had a read through the forum and generally people are more talking about start up smoke and the like, not really what I'm seeing with mine.

If this had already been answered elsewhere then please point me in the appropriate direction... Many thanks for the advice as ever. Also if I need a visit to MRC (does Doug still watch the forums?) for a bit of a manifold make over then let me know, I've been promising myself that for a while!!

All the best,

Sarge

p.s. if anyone's got a recommendation for a detector that knows the live locations of the M25 gantry traps that would be awesome.

[ArthurPE]

doesn't sound normal
what color is the smoke?
did it stop after blowing it out a while?
what is your oil consumption per 1000 miles?
how about coolant?

mine will smoke if crusing for a while then getting on it, otherwisr very little, except a bit while warming up (un-burnt fuel)

[TimDogg]

Agreed - go and see Doug, doesn't sound right.

[adsgreen]

Not normal.

My first instinct would say a failed piston/scraper ring.

Under load there may be enough compression in the cylinder to form a decent seal but at idle the oil gets into the combustion chamber.

Would be even more noticeable if just after a motorway drive as oil hot and thin.

Not as obvious at cold start as the oil is thicker.

How old is the oil? How much are you using?
The smoke - was it white, black or pale blue?
If oil it'll smell like a burnt clutch.

I would get a compression and leak down test done ASAP

[adsgreen]

Oh fwiw carbon usually comes out in chunks and you tend to see sparks out the exhaust.

[sonny]

Overfilling the oil level could also cause this, iv seen this on another Audi Model. Was a hell of a lot of smoke. Hopefully its this and will be quick and easy to rectify.

Funnily, I saw a B8 a few days ago that was producing a lot of smoke (white), may have been vapour.

[DaytonaSarge]

Morning chaps,

Thanks for your input. In response:

Smoke was white, I use about a litre every 1000/1500 miles (as I have since I've had it) and haven't noticed any loss in power or other such issues. Only recently have I noticed excessive smoke and it certainly seems to be more prevalent at idle. On a run though it soon clears and doesn't happen, although I have noticed when pulling off from traffic lights I get a bit of a cloud as well...

Last full oil/filter change would have been August and I put a litre in it a couple of days ago...

[adsgreen]

The other thing it could be is a faulty cyclone separator.
If this isn't working then blow by oil will go straight back into the intake manifold.

[DaytonaSarge]

Shouldn't be an over fill, I had the yellow warning come up on Saturday and put a litre in it then... maybe I should check the dipstick more often!

[DaytonaSarge]

Just checked and the oil level is barely over the min on the dipstick... that's after chucking about a litre in on Saturday..

[adsgreen]

Lets recap
- service in august so 6 months of new oil.
- chucked in a litre and just on min - so its lost at least 2 litres of new oil in 6 months.
- smoke out the back when not on load.

pretty conclusive it's burning the oil really. The question is how...
- piston ring. Check with compression test. This would be the first thing I'd get done PDQ. Doesn't have to be a fancy garage - any decent Shop should be able to do this.
Hell, it's not hard to do yourself (IIRC just disconnect fuel pump, run engine until it dies, remove spark plug, fit compression tester, turn over engine, record reading, repeat).
Worth doing a leak down test too.
- Cyclone separator - seen afew case of this breaking. If this has gone then oil will be getting into the cylinders. but to be honest, even with this broken thats a lot of oil.
- valve stem: seems an awful lot of oil to lose so whilst possible I think worth checking elsewhere.

Hmmm - worth checking for an oil leak - might be dripping on something hot.
get somebody behind the car to confirm it's actually coming out of the exhausts.

[spikeyboy101]

Cant help on the oil issue.

But the Road Angel devices are good for picking up the live speed cameras.

[sonny]

any updates on this one?