a44mark

My 2012 A6 3.0T is out of warranty and, thanks to learning on my previous car (2002 A4), I've decided to tackle as much of the maintenance as possible. I'm approaching 55k miles, and that service is one of the big ones. Included in that is replacement of the spark plugs. I know there's a writeup or two in the B8 S4 forum, but I haven't seen any specifically for the C7 A6, so I figured I'd have a go at it.

I spent a couple hours on the Audi "erwin" site and downloaded all of the relevant repair & maintenance manuals in PDF form - not bad for $35 as long as I'm not missing anything. They seem pretty comparable to the level of detail in the old Bentley manuals.

On to the job!

I started with the passenger side. First I loosened the clamps on each end of the air intake tube and removed the end connected to the filter box and moved it out of the way. That gives enough clearance to access everything easily.




I then removed the 2 torx screws holding the coil pack harness down, unhooked each of the connectors, and slid the whole harness down and off the coil packs.

Removal of the coil packs themselves was a bit tricky, only because they were stuck in there pretty good. I didn't have a removal tool, so I used channel lock pliers on the red casing and pulled straight out. I replaced each plug one at a time so I could keep track of the condition of each plug, just in case I found one that looked unusual. Fortunately, they all looked identical:



I used OEM plugs as replacements, using anti-seize on the threads and dielectric grease on the inside lip of the coil pack boot as instructed by the manual. Tightening torque is 30 Nm, or 22 foot pounds.

The driver's side was a little trickier because the coolant reservoir needs to be moved in order to get clear access to the coils/plugs, but the main coolant hose on the bottom doesn't provide much leeway. I unscrewed it from the bracket and disconnected the level sensor on the bottom. I was able to move it enough forward and to the side to get sufficient access - not as good as the passenger side but good enough.




I also unhooked the clip that holds part of the coil pack harness to the head in order to get more slack in the harness.




Overall, the job was very straightforward. I estimate it took me about 1.5 hours, mostly because this was the first time on this car.

Hope this is helpful to someone... Next up is the accessory belt!

-Mark

BillBoost37

Looks great, I'm about to do the ones on my 2010 A6. Same procedure and overall should be a snap.

2008A6

Nice write-up! Are you replacing the supercharger belt yourself too?

allenst

if no tool

I've seen people use 2 plastic tie belts wrapped around each end to pull up on

a44mark

Yes, although it's not due until 75k I think. Oddly, the SC belt has to be removed in order to replace the accessory belt, so I'm tempted to do both...

-Mark

2008A6

Hmm, not too sure about that. My tech had said it was the front supercharger belt that calls for replacing at 55K. In the 2012 Audi Maint Schedule, it says replace front V belt for compressor drive at 55K for A6 3.0T.
Let us know if you learn otherwise..

tenspeed

Thanks for the DIY.

What kind of plugs are recommended for supercharged engines? What were the OEM plugs? I prefer Bosch or NGK platinum or iridium single electrode plugs for NA engines.

IknowHuhA6

Yes Nice write-up. When I replaced my plugs, the hardest part for me was snapping off the coil pack connectors as I was afraid to break any clips. I agree, overall pretty easy. I did have the benefit of a friend helping me move the coolant reservoir out of the way as needed for driver side plugs. Second time is easier = )

My personal opinion on plug types. Stay away from platinum plugs on any boosted application. Just my 2 cents being I've been tuning SC engines for years. Get more risk of knock as platinum tends to absorb heat more than copper.

BillBoost37

On plugs, I did bring up the question and got some good information.
https://www.audiworld.com/forums/a6-...0tfsi-2884529/

I went with stockers as my replacements. Maybe this weekend I'll carve enough time to drop them in if I'm not on a trip to Long Island

IknowHuhA6

Bill thats a great post thanks for sharing. Very good point that i forget most just want longevity and ease of maintenance, so the platinums are preferred in that case.
i just happen to be an odball that likes working on my car and dont mind replacing plugs sooner. = )
"Scotty i need more power" lol.