2006 Jetta shuddering, oil residue on block

Since early in my TDI's life I have had "shuddering" occur intermittently while idleing, usually after slowing down at a stop light or stop sign.

Now this is a daily issue, some days it is light, others it feels like I am only firing on three instead of four. Flippin' pisses me off.

About three months ago I had a CEL for a bad glow plug and low power symptoms. Dealer replaced glow plug and car seemed to run better, started better for sure.

I have noticed that the shudder is usually worse in Albuquerque, NM than in Las Cruces, NM where the elevation difference is several thousand feet higher in Albuquerque.

I think I am going to fiddle with the MAF tomorrow as I have read here that that may be the cause of the shudder.

This morning while changing my oil I noticed that rear of my engine, beneath the turbo, is covered with a lot of residue on the block, on several hoses, and all over the actuator which is wrapped in a reflective insulation blanket with button snaps holding it around the actuator. At first I thought it was a small oil leak as I saw some residue on the cross member just rearward of the oil pan, but then I started looking closer and it looks like I am getting exhaust blow-by from somewhere.

I make long high-speed trips (3.5 hrs at 85-90mph straight, no stops, no slowing down) so I don't think I would have a plugged egr, but why am I getting all of this sooty, oily residue behind my engine???? I have owned 5 diesel trucks and never saw anything like this.

Stats:

54000 miles on unit
42-44mpg @80-90mph
Blackstone labs reports no unusual wear


Comments?

I think most would agree you aren't experiencing anything abnormal. These things do seem to generate some blowby. As long as your oil level isn't going down significantly and the oil isn't puddling in the belly pan, I wouldn't worry about it. On the decel shudder, I experience it too but I have noticed that if I engine brake it doesn't do it. I think it has something to do with tuning and nothing more. That's my two cents.

yeah, I always engine brake and it wont do it then. I too think that it is a fueling issue/air to fuel mixture issue.

My main concern is that literally the actuator and surrounding surfaces are COVERED in black sooty oily residue (like the residue on the rear bumper, I am sure you experience that too as we have the same color car!), where is this coming from? Does this thing have a wastegate? If it does, the wastegate should be "wasting" clean air, not sooty air....Unless my Turbo is on its last legs...then i could see how that might be possible. But I have noticed the residue on the cross-member since early on in its life, so I dont think that this is from the turbo.

You don't have a wastegate, you have variable vanes.

And a wastegate "wastes" exhaust gasses, not inlet air.

sfoote said:

yeah, I always engine brake and it wont do it then. I too think that it is a fueling issue/air to fuel mixture issue.

My main concern is that literally the actuator and surrounding surfaces are COVERED in black sooty oily residue (like the residue on the rear bumper, I am sure you experience that too as we have the same color car!), where is this coming from? Does this thing have a wastegate? If it does, the wastegate should be "wasting" clean air, not sooty air....Unless my Turbo is on its last legs...then i could see how that might be possible. But I have noticed the residue on the cross-member since early on in its life, so I dont think that this is from the turbo.

Click to expand...

Yeah definitely sooty on the back! By actuator do you mean wastegate actuator? As whitedog already put it, variable vanes--no gate. I took my EGR valve apart a while back and it wasn't real bad. Just keep the old foot in it to keep it clean.

Yeah, what I meant to say was that if I was experiencing loss of boost from somewhere like the IC hose It would be clean air. I have noticed a small loss in performance and kind of a "dead-pedal" and "dead mid-range" feel lately and I was wondering if it had to do with a loss of boost and then I saw the soot and got to thinking that perhaps I had an exhaust leak and/or a pre-aftercooler hose leak. Sorry, got two different thoughts mixed up. Ill drink some cofee first next time

the actuator seemed to move pretty freely, I could feel the spring pressure and the rod moved smoothly, but with a gritty feel from the exhaust particulates/accumulated dirt.

I tried cleaning the MAF today and I thought it made a noticeable difference for a while, then the shudder came back.

On a positive note, I filled up today and got 44.53mpg mixed city highway with some really hard pulls after getting aggravated at the shudder. I guess "summer" fuel is back, usually I am around 40-42.xx mixed city highway. Of course it could be that I stopped using PS two tanks ago when the shudder started really getting bad.

I am at a loss for words, I dont like it when anything I pay for is this aggravating. I should have never sold my powerstroke, though overall this car is saving me $$.

Sfoote - have you checked out this thread about the shudder at stop lights? http://forums.tdiclub.com/showthread.php?p=2129303#post2129303

Could be a timing issue and is perhaps unrelated to leak/soot issue.

My car is leaking a little oil at the turbo inlet. I'm just monitoring the oil loss, rather than bringing the car to the dealer for them to play around with it. That makes me more nervous than having to add a little oil now and then.

I've never had to add any oil, engine does seem to seep/sweat/leak a little somewhere. I have since been able to transform my driving habits somewhat to kinda eliminate the shudder at stops.

Our A5 would stumble at stop lights and run rough too. Has gone away since I put in the VR6/G60 clutch after the DMF failed.

I too have seen oil on the back side of the engine. Every one of my valve cover bolts were loose! No more oil leaking after finding that. I think it might need blue lock tite.

The big fat intercooler pipe on the front passenger side that looks like an upside down "V" ... ours would leak there and it turns out the seal changed. Ours (build date July 05) originally had a black one and dealer replaced with a green one. Seal must not have been lubed when reinstalled because it rolled and got pinched and leaked again. I rotated the pinched part of he seal to be at the top, lubed it and installed it again and it hasn't leaked there anymore.

Your mileage my vary but that has been my experience with our A5.