Piston Slap: Mounting Problems Amid Audi Uncertainty?

Sajeev Mehta
by Sajeev Mehta
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piston slap mounting problems amid audi uncertainty

TTAC Commentator jrominski writes:

Nice to see you are still at it on TTAC. (Back at it?)

So my story is a 2010 Audi A4, Quattro 2.0t Premium. Red, as it should be (No, it should be brown. Duh. – SM). Just turning 60k miles. The engine is an EA888 according to Wikipedia, twin chain driven counterbalance shafts as is known to work so well on I4s. Production commenced 2008 and its in all US A4 B8s with the 2.0 gas engine. Inside oil cap the gallery is clean as can be, I keep the VW spec Mobil 1 changed with my mityvac. New plugs, NGK of correct part number, air cleaner path is fine. The rest is original unmolested.

The issue is it runs rough. Slightly, as in the car does not shake but I feel it. Worst, dead cold, running at just above idle up a slight incline. A miss. Since 25k. Goes mostly away when warm or when power is asked for. No codes. Sort of feels like a tire flat spot but it did not go away with new tires.

Dealer responses on different occasions from mile 25k through mile 60k (all same dealer.)

  • (15 minutes after drop off, motor still hot) It does not run rough. Our service guys could not replicate the problem. You should be using top tier gas. (I hand him a printout from www.toptiergas.com and suggest generating a handout for the service department to give customers instead of just telling them to go look it up on internet.)
  • It runs rough because you have the old, non-counterbalanced engine. Its a 2010. Buy a new car. The news ones do not do this.
  • It runs rough but does not throw a code. We can’t help. What gas are you using?
  • It does not run rough.
  • It runs rough because of intake sludge. We will fix it for free right after it goes off warranty. Top Tier in the mean tine.
  • You should be using that there top tier gas. Run some Chevron through it. (I buy mine cheap at Costco)

A friend with VAG setup ran a diagnostic and it has no codes, except for a heater flap ran out of limit once. It sat there idling kind of lumpy and no misses were recorded anywhere.

Friend says:

  • All Audis have crap motor mounts. He flexes right mount up on lift with a tire iron, it moves a bit. Its fluid filled, should flex. The mount has a sensor and would throw a code.
  • If it had a miss the O2 sensors would pick it up and if it were serious the Cats would fail. They are fine. Its your imagination. All new cars suck. Freaking Japanese. Buy an old Panther (Obviously, esp in Brown. – SM) or a new Focus.

I am doubtful motor mounts are what it is. This guy makes his living doing off-warranty work for Porsche Audi dealers all around Boston, engine controls and sensors. The dealer warranty payment from Audi is low enough that they will not ever perform any real diagnostics under warranty: no code then OK let’s back it out of the shop!

Sajeev answers:

OMG SON! I mean…

  1. Even with my corporate full-time gig, the eldest TTAC scribe’s been reliably posting to the Piston Slap series twice a week, but there’s still a question that I’m not a regular contributor?
  2. Your last paragraph, the section I entered in bold face: an Audi specialist tested the engine mount, it CLEARLY failed no matter what the sensor reports, and you don’t believe him?

More to the point:

Look, I understand your lack of Audi knowledge (of which I’m guilty too) and our country’s general mistrust of any mechanic (ditto)…but…

I had a similar problem after my (then 13-year-old) Lincoln Mark VIII had a bizarre vibration/miss around idle. I gave up and went to my trusty mechanic. He fired it up, opened the hood, put his foot on the brake, put it in gear and pressed the gas: the motor lifted up like the nose of an Airbus on takeoff. Granted a Ford liquid-filled mount lasting 13-ish years and 150-ish thousand miles is a little different than your situation, but if your mechanic friend says that Audis have “crap motor mounts” you go right ahead and believe him!

Fact is, just a millimeter (or less) of variance in any powertrain mount is a concern. The sensor hasn’t been tripped yet, but that’s irrelevant.

Case in point: once again, my Mark VIII. The fairly complex aluminum differential/IRS setup had an annoying vibration above 80 MPH. On a whim, I replaced the four rubber mounts because one looked somewhat smushed (technical term) compared to the others. Considering my driving style in a modified, Hot Rod Lincoln, perhaps that fraction of a millimeter meant something. Lo and behold, it did.

Take it from me and your Audi-wrenching friend: GET NEW ENGINE MOUNTS!

Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.

Sajeev Mehta
Sajeev Mehta

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3 of 42 comments
  • Johnny ro Johnny ro on Nov 13, 2013

    Some good advice here particularly to chill about it, although I actually am cool about it. A 1/3rd worn out A4 is a really good car. If you want a german car horror story ask my nephew about his late model 5 series in which the VANOS assemblies came unconnected inside there all by themselves and it was a $9,000 repair. Bolts backed out except for one which finally sheared. Died in his lot at work, moving at 3 mph and not in a parking spot. Recently out of warranty. BMW picked up the tab during the third day but its still a horror story. We are talking nuts and bolts here. So no, not a couple tanks of good E10 will fix this slightest of misses. I use mobil and shell. One time out of ten, costco cause of their great steaks. I also use costco for my techron. I know people without access to top tier and they don't have problems in their DI audis. Service manager out for a ride with me. -Do you see what I mean? -No. -OK. Do you feel it missing? -Yes. What gas do you use? -E10 just like you. -Huh? -E10. It sucks. I buy it from shell or mobil. What am I supposed to do for good gas? He gave me the tiny plastic bottle of gas treatment with the VAG part number for free, made no discernible difference just like the techron. I think its not the mounts, although I will fool around with shifter as suggested above. I am not really worried about it. I am looking for a Karmann Ghia to play with and that will shake a lot more. I eagerly look forward to snapped throttle cables and loose distributors and oil leaks and king pin adjustments all that. This miss is nothing like what you see people talk about on Audiworld with actual shaking and lights flashing and stalling and all that. Its faint then goes away. Nobody I know would notice it. I do listen to the car with the music off for the entire ride. And I drive 125 miles oneway twice a week, then 12 miles one way eight times a week plus random other amounts. I support this dealer because they are basically nice people, and I want them to stay in business. I pay them to change my brake fluid every second year, tagging myself in their system as affluent and also a regular non-warranty paying customer. I give them straight tens no matter what; they stare at me and I stare back when they lift their eyes from the screen and we both nod. They do nice things for me now and then. I was hoping you would all pick up on the irony of their many versions of an explanation particularly including that early EA888s don't have dual chain driven balance shafts. Oh really. I bought a harbor freight snake camera and the head is too big to fit in anywhere unless I pull the manifold. I might do that when my next second car is up and running reliably. Cheers! Thanks Sajeev.

  • Tinker Tinker on Nov 14, 2013

    Run a can of Seafoam through it. I get mine at the local O'Reillys. Not sure if the Seafoam is compatible with O2 sensors, but you wanted to do something and if the sensor fails it will show a code, in any case.

    • Mrb00st Mrb00st on Nov 14, 2013

      Seafoam won't do anything on a DI motor, though.

  • MaintenanceCosts So there is no Sonata trim without some type of Theta engine.It seems like they've been doing a bit better when attached to a hybrid system, so that's probably the one to get, but they're going to have to go several years without further engine troubles before I'd trust a H/K ICE product again.
  • Lou_BC Full sized sort of autonomous RC's. Cute.
  • Art_Vandelay Autonomous capabilities are being deployed (or planned anyway) in multiple combat vehicles. Should be fun from my perspective
  • Drew8MR Interior is trivial now you can get repro everything in various levels of quality. Getting the top sorted will be a couple grand, but I'd drive it as it. I drove a $1500 67 GTO convertible for 20 years, not every old car needs to be like new.
  • John Not everyone pays that much for power. Mine is 10 cents per kw…..