2006 A6 3.0L Quattro TDI auto - white and blue smoke

[Boarder23]

Hi guys,

I'm looking at buying this car, it drives really well, but it puts out some white smoke, both cold on idle and when it's been running for 10 mins or so held at 1500rpm. I took it for a quick spin up the road, gave it a boot full to check the turbo and to see if the white smoke would clear, but it gave a puff of blue smoke under hard acceleration when under load. It pulls really well and there's no rattles or whines from the turbo etc.

Seller says it hasn't consumed any oil.. but it was defo blue smoke.

I'm thinking injectors for the  white smoke, possibly turbo seal for the blue? I'm thinking it wouldn't be head gasket or valve seals because it doesn't put out blue smoke on start up and it runs really well. There was also no signs of cross-contamination at the coolant reservoir and the oil filler/dipstick.

I'm looking at it more as a project, any ideas? It's cheap enough that if it's a total dog it won't make me cry too much. I just want to figure out what it could be!

It's the ASB engine model, with just under 160K

Edited March 31, 2023 by Boarder23

[Stevey Y]

44 minutes ago, Boarder23 said:

Hi guys,

I'm looking at buying this car, it drives really well, but it puts out some white smoke, both cold on idle and when it's been running for 10 mins or so held at 1500rpm. I took it for a quick spin up the road, gave it a boot full to check the turbo and to see if the white smoke would clear, but it gave a puff of blue smoke under hard acceleration when under load. It pulls really well and there's no rattles or whines from the turbo etc.

Seller says it hasn't consumed any oil.. but it was defo blue smoke.

I'm thinking injectors for the  white smoke, possibly turbo seal for the blue? I'm thinking it wouldn't be head gasket or valve seals because it doesn't put out blue smoke on start up and it runs really well. There was also no signs of cross-contamination at the coolant reservoir and the oil filler/dipstick.

I'm looking at it more as a project, any ideas? It's cheap enough that if it's a total dog it won't make me cry too much. I just want to figure out what it could be!

It's the ASB engine model, with just under 160K

Hi treble smoke is very possibly is either valve stem seals or a sticky compression ring, turbo seals I doubt but an easy check is remove the intake for the turbo and manually pull the vane boss up and down and check  back unforward for end float should be about 1mm up and down with no end float from side to side, I would also be checking for scanned faults and any history of cam chain replacement as at that milage all four chains are well on their way, if its dirt cheap buy it and run it until it dies, turbo recon about £600 for the part and a cam chain change anywhere over £3000.

Steve.

[Boarder23]

No service history with the vehicle, seller has only owned it for a year. There's no rattle on start up. What do the chains usually last for?

How would you check for piston rings? Compression test?

[Stevey Y]

1 minute ago, Boarder23 said:

No service history with the vehicle, seller has only owned it for a year. There's no rattle on start up. What do the chains usually last for?

How would you check for piston rings? Compression test?

Hi any garage should be able to check the compression electronically, chains can last anything from 60k to 200k dependent on oil service and oil grade used and they won't rattle on start up way before that you will develop what seems a misfire which is the crank/camshaft synchronisation going to pot, the chain guides are made of nylon and are prone to wear or breaking up, thats why I suggested getting a diagnostic scan as if there are any faults to do with the timing, walk away, there are a few of them on here that have had cam chain problems with much lower milage, at the end of the day the whole car has done in excess of a 100k and everything is tired suspension, engine, gearbox and speaking from experience with my car at 150k I am experiencing suspension bush failure and that is not cheap, given the age of the vehicle and the milage unless you intend to do a lot of the work yourself I would be inclined to get something else with less miles, its cheap for a reason.

Steve.

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[Magnet]

Hello Natalie,

A cheap car will always be a cheap car however much money and time it consumes. 
No offence meant, but if you are asking the type of questions you are, then it suggests your knowledge may not be sufficient to sort this out without assistance. 
My advice would echo Steve’s, and I would be giving this a miss unless you are prepared to put up with it as it is, and you know someone who might take it off your hands at a similar price to what you have to pay for it. 
Current owner for one year? Why sell a good car after one year? 
My feeling is you will most likely buy this - because it’s cheap. I could be wrong, but that’s my gut feeling.

Kind regards,

Gareth. 

[Boarder23]

I appreciate the polite response but what questions am I asking to give you that impression? I have plenty of mechanical experience, just not with turbocharged cars, I am looking to do the work myself. I just wanted to check if it's a common problem or if this was something someone else had come across. No point struggling if someone else has already been there and solved it.

I was looking for an auto car for the short term but this came up and I was wondering if it might be something I can buy cheap and work on to make better, a project as such.

He's just had a child, and needs a more suitable car was his reason for selling.

Edited March 31, 2023 by Boarder23

[Steve Q]

I wouldn't trust the sellers reason for selling. Service history is key on any German car. German cars get cheaper to buy the older they get but maintenance costs always remain expensive. 

Could blue smoke be injector seals? 

Either way I think you'll be looking at a lot of repair bills in the not too distant future which is why I think the seller is selling. 

Has the gearbox been serviced? 

As the saying goes, if it sounds too good to be true it most often is! 

[Boarder23]

5 minutes ago, Steve Q said:

Could blue smoke be injector seals?

That was one of my thoughts, especially as there's slight white smoke at idle, one or more injectors could be bad and seals may be going.

The other theory being could the PCV have gone bad, causing blow-by and making it look like bad piston rings. It's just all educated guesses.

Edited April 1, 2023 by Boarder23

[Steve Q]

Well I go from my experience on my old A6. I have blue smoke on start up. It's not glowplugs as they've been changed and no fault codes so in my case I think it's the injector seals.  

Either way it sounds it could be expensive and a long drawn out project.