George Trudeau

Hey everyone, 2006 A4 Cabrio 1.8T CVT, 118k miles, non-quattro

My daughter came home from school today, rolled down our driveway where I was working on our other 2 broken cars, exclaiming that her car was smoking pretty bad. I look up and see slight blue haze on the street. I also smell, what seemed to be diesel smoke. She said it smokes really bad sometimes over the last couple weeks. So, I took it for a drive. It seemed fine for the first few miles. As I came up the big hill that leads up to our neighborhood (very steep incline, about 3/4 mile long) I made sure to really get it hot. I kept the turbo spinning hot all the way up (t's a very steep hill). After I let off as I crested the top of the hill to the stop sign, I saw a LOT of smoke behind me. As I turned into the neighborhood and down to our house it continued. It smelt mysteriously, like diesel.

I am a little stumped, but have 2 theories.

1) She accidentally put diesel fuel in? (which I thought was impossible now, as the nozzle shouldn't fit in the neck).
2) She over filled the oil. It has used some oil ever since we bought it; maybe 1/2 quart every couple months. I believe she may have gotten in the habit of dumping in an entire quart when the light goes on (as we know, these cars only hold 3.5 quarts).

Some more useful info- No CEL lights are on, and it seemed to run fine. Totally normal. Some mild hesitance at low RPM with the annoying CVT transmission dynamics. Turbo spools fine, everything seems normal.

Thoughts??

~George

lyleswk

Woodinville...nice town. My son opted to move to Kirkland to be closer to his friends; I wish he had stayed. Anyway, assume you asked her if she might have done one of the 2 items you mentioned, but doubt the diesel theory is true. Don't think gas engines don't have enough compression to ignite the fuel.

Overfilling could be true and if it is, you need to drain some of the oil or will damage the engine. Other than that, assume you have opened the hood and looked around for an obvious leak. That much smoke should have a visual indication. Check oil filler for tightness and maybe the filter as well.

turbo510

Maybe a turbo seal. Pull the throttle body hose, and check if the throttle plate is oily. That would indicate a compressor seal. If not then pull the plugs for a look. Any of them oily means that engine oil is getting into the cylinder, either through a valve seal (unlikely I think) or a broken piston. If all that looks OK, maybe the turbine end of the turbo is leaking into the exhaust. Also, a PCV blockage can cause increased crankcase pressure, and even blow out the rubber plug under the cam chain adjuster, allowing oil to leak onto the cat.

George Trudeau

Yes, we love it here!

Yeah, I don't think the diesel theory would hold true either- it was just more of an observation based off of the smell of the exhaust. Also, the car isn't leaking- Let me be more specific. The smoke is coming from the tail pipes. Not dripping on hot exhaust or anything like that. It's quite clearly something going on inside of the engine, which is pretty discouraging.

~George

George Trudeau

This is fantastic advice- I will look at these! All completely reasonable and explainable. Also, more hopeful in terms of repair. Well, except for the cracked piston. The car runs fantastic though.

Stay tuned!

~George

George Trudeau

Well I looked at this a couple weeks ago and found some things. Firstly, the intake was all clean. No issues there, so looks like compressor seal is fine. I then looked at the spark plugs, and this is where it got intriguing. The tips, looked fine. Old, but otherwise fine. What was interesting, was the threads. About half of the threads were logged in oil (from the top, down). Mostly an issue in #2 & #3 cyls. The front & rear plugs (1 & 4) had a little, but nothing like the middle ones. The porcelain insulators and galleys were covered in oil. I am not sure what to make of this??

My only thought, is maybe my daughter was VERY sloppy in adding oil at some point and it didn't all make it in the fill hole and has run down the top of the cylinder head and somehow, the oil is seeping into the spark plug holes?? I wouldn't think it'd create as much smoke as it does though.

The smoke is coming from the exhaust pipes, so nothing is dripping on the cat. Maybe the turbo turbine is leaking at this point. Is this a common failure? I mean, the car doesn't have THAT high of miles... 119k now.

George Trudeau

Some pictures here....

turbo510

Not too unusual; the valve cover gasket needs replacing (and the plug wells need to be swabbed out with a cloth twisted on a stick. But this doesn't explain the oil smoke. If the plugs all look like that, and smoke is definitely coming from the exhaust, that leaves the turbine seal as most likely in my opinion.

George Trudeau

Thank you very much for your help, Sir. The plugs do all in fact look like that, and it is definitely coming from the exhaust. Thank you for your assistance! I will start researching that R&R. Not sure if that is doable by myself or not.

~George