A4 2.5 v6 avant black smoke

[Box760]

Hi guys I know nothing at all about cars I'm due a service and have an oil leak so I went to an ATS today to see about the leak the guy told me not worry about the leak but be more worried about the oil coming out of the exhaust he said he could tell from the black on the rear of the car I knew it was out kicking a bit of black smoke when I put my foot down but I thought that was down to the fact it was due a service oil and fuel filter and what not now I am worried thinking what it could be the cars driving perfect.

[zollaf]

they do produce a small amount of black smoke when you boot it, this is ats after all, who refused to respond to an email from a moderator called eshrules about their service as complained about by another forum member.
welcome to the forum.
find yourself a garage that is small and friendly and not part of a big national chain. get this garage to carry out a service and see if they think there is another problem.

[gupsterg]

Hi Box760 ...
Welcome to the VWAF ...

RE ATS Link:- Dave - ATS Kidderminster

I'd defo get second opinion from another garage and don't state what occurred at ATS see what they say first ...

I have a 2005 A6 3.0 TDi and don't ask how many new bits it has on engine when booted or spiritedly driven it will exhibit black smoke puff ...
I was watching a doco on Le Mans last nite and even the highly tuned diesel race cars by Audi and Peugeot can puff some smoke out ...

Perhaps post some pics or take car to a quiet industrial estate and get someone to video you driving it and post to get opinions on level of smoke ...

[Box760]

Cheers but if you need a new fuel and oil filter and oil change would more than normal amount of black smoke be expected and would it leave the back of my car dirty.

[gupsterg]

Only in my experience as an owner a well serviced vehicle will smoke less / run better ...

I'd get the service done or are you having other problems than oil leak to make you question the amount of smoke?

Black Smoke

Black smoke emitting from your exhaust is due to a air to fuel ratio imbalance. This occurs when the diesel fuel system is delivering either too much fuel into the engine or there is not enough air.

Below are some ideas of what is causing your vehicle to emit black smoke:-
* Faulty Diesel Injectors
* Dirty Air Filter
* Faulty Diesel Pump
* Valves clogged within cylinder head due to EGR being faulty.
* Intercooler or Turbo Charger faulty

Extract from Link:- Troubleshoot a diesel engine

[Guest 2]

Black smoke is usually unburnt fuel. As above, do a full service first including all filters and see what happens.

Does it smoke like this lol? Altho this is a bit ott as its a french scrapbox

[Box760]

No where as near as that I have a poor sense of smell but I couldn't anything the guy at ATS was trying to say he's thinks it may be the cylinder head but surely i would be able to notice a dip in performance

[gupsterg]

In the video that Chris has posted you will see the black smoke at beginning of rev'ing due to too much fuel setup to give extra power once NOS enabled ...

Here's info from the YT video poster :-

the smoke clears only when nos is used without nos it smokes all through the rev range

So why is the NOS clearing the smoke because it provides more oxygen as it enters/breakdown with combustion process and sorts the imbalance of fuel to air ratio ...
Watch video on YT, view comments, the owner has done loads of mods to get more power by pumping extra fuel/air into it ...

So you can see the list of stuff in post 3 is related to fuelling/air ... I'd started doing cheapest fixes first ie service ...

Also do get a second opinion before you plough unneeded £££ ...

[NickPicks]

No where as near as that I have a poor sense of smell but I couldn't anything the guy at ATS was trying to say he's thinks it may be the cylinder head but surely i would be able to notice a dip in performance

I think you should ignore anything that anyone at ATS or Kwik-Fit type places has to say about anything. They can barely fit tyres properly, and even I can do that!. I'm sure that there are some people who work there who know what they're talking about, but from the anecdotal experiences I've had and heard of, they're in the minority.

Take your car to an independent garage, preferably a VW/Audi specialist and ask their advice. If it's due a service anyway, get them to do the service and advise on the oil leak and smoke. Have a look in the recommendations section here

The smoke could just be that the air filter is a bit clogged up.

So, the ATS guy said to worry about the oil coming out of the exhaust, as it was making the back of the car black? Does he know when you last washed the car? The back of my petrol car is black when the roads have been wet and dirty. he then said it might be the cylinder head? If the cylinder head or gasket had failed, I'd expect it to be overheating or producing white smoke(actually steam). If it was leaking oil internally, I'd expect the smoke to be bluey-white. Black smoke is usually that there's too much fuel being injected for the amount of air, which could be caused by a few things.