drunkenup

I posted a month ago about my 2010 Q5 3.2 PP suffering from excessive coolant usage and that went well and all but only a week after the car started suffering from another ailment.

<iframe width="560" height="315" src="http://www.youtube.com/embed/MxVrImcNkZI" frameborder="0" allowfullscreen></iframe>

Rough start up sequence where it would take a while to crank, and when it did it would fluctuate rpms and shake around. On two occasions when we left the car to sit it would be bad enough that we would require 3 attempts to start. Once on the road car would feel like it lost a hundred horsepower, and eventually shot a CEL on the instrument panel. I thought it was bad injectors, but turns out to be carbon buildup.

Bad news is that it is carbon buildup, so it will be at the dealership for some time while they contact AoA to see what to do next

Good news is that while our Q5 is gone we have a 2013 A6 3.0T to play with (very good news). Awesome machine, awesome engine.. would pick up an A6/S6 tomorrow to replace my Mercedes. Also, we took the car in with 49920 miles, and the dealership said they would honor the warranty for any recurrent problems even after the warranty expires, carbon buildup included.

flybooey

Did all of this go down suddenly and then consistently until you took it to the dealer? Or would it go away for a period then pop up again?

Do they still have to drop the motor to address this?

Dave

drunkenup

If you carbon problems too, you probably won't notice it until it starts coughing up like in my video I took.

Even before it went in for the coolant problem (3 weeks ago?) it would have rough starts when cold every once in a while. The first occurrence perhaps 2 months ago, and didn't happen again until a week or two later. It happened more and more often and eventually it became difficult to start in one try.

If you know what it felt like new or if you can compare to a healthy example, you may be able to spot a loss of power before the rough starts. When it went for coolant before the starts got real rough, we were given a 2012 3.2 Q5 with 6000 mi which felt far more effortless in acceleration than mine ever has. After it started putting up the CEL and failing to run in one try it then felt like it lost another 100 HP.

My service adviser left a message with the diagnosis on friday just saying they need to contact AoA, which is something they need to do for an issue this big I guess. Don't know exactly but I'm guessing they will need to drop the engine for this fix as I've seen elsewhere.

spijun

Here you have all of the carbon build-up:
https://www.audiworld.com/forums/sho...2816385&page=7
https://www.audiworld.com/forums/sho...uildup&page=24

Good luck

ELEVENS

God (or more precisely, Audi NA) help us all!

scottndsky

You guys are starting to worry me. I just bought a 2010 3.2 with 17k miles on it. Did I buy a ticking time bomb? Is there anyway to prevent this problem, or should I start thinking about selling this nice low-mileage car I managed to find?

MartinQ5

I had the carbon buildup problem too but didn't notice anything performance wise. The engine light turned on for a while (few days) and then turned off for two weeks before turning on again. I went to the dealer as it was close to the end of the warranty and they confirmed it was triggered by carbon buildup.

They had to tear down the whole engine to fix it... Now I am thinking about selling my Q5 before the problem appears again...

Bleh5

OP, where do you live? Only reason I ask is, that reading the other threads, it seems like mostly people in cold-weather climates are getting this issue.

itsasecret

There are 2 areas of carbon build up. One being the backs of the intake valves which will cause running issues. Second being the secondary air passages can clog up which "should" not effect running. Both will set a check engine light. The secondary air passages tend to clog up around 35k miles. Misfire faults set for the carbon on the back of the valves and secondary air pressure faults set for the secondary air passages clogging. I hope that clairies things a little.

DennisM

Maybe you'll get serviced by the traveling AoA Roadshow which does not require dropping the engine (only removing the bumper) and uses high pressure water. See the first link above by spijun and scroll down to the comments by McBogey.

It's great that they're saying you'll be covered in the future.