RS5 PCV inspection and carbon buildup

A5/S5/RS5
#1

This evening after I got back from Atco Raceway, I still had my buddy’s RS5 so I thought that it would be a good idea to tinker and look around a little bit. I got permission to take things apart and look before removing anything. Also PsYkHoTiK asked about carbon buildup on the RS5s so I was interested.


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Took the big middle engine cover off and there are two PCV valves. One behind each throttle body. Each valve cover has a line that goes off it to the corresponding PCV valve. That is different from the other FSI V8s. The B7 RS4s have a plastic line that comes of each valve cover and then merges into one line at the one PCV valve on the back of the intake manifold. The low revving FSI 4.2s like in the Q7, 2007+ C6 A6, 2007+ facelifted D3 A8s, and B8 S5 coupes have one plastic line that goes off the driver’s side/bank 2 valve cover to the PCV valve and then the passenger’s side/bank 1 valve cover is capped off.


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I took the cap off the left/driver’s side PCV valve and the rubber diaphragm and spring came off with it. This is a different style then the low revving S5 that I have been working on recently. Part of a flap of the diaphragm is going through the end of the spring. There was also traces of liquid oil inside the PCV internals.


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My buddy was curious of carbon buildup on this car. It has just over 26K miles and he hasn’t been driving it very much lately since he has been playing with his other Audi. So I got a chance to try out my Snap-On camera some more. I took off the driver’s side intake hose from the throttle body and then snaked this camera down into the intake manifold.


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After a few minutes of wiggling the camera end around and playing with it to get it directed at the valves, I saw this. It would seem that the RS5s have three piece plastic intake manifolds just like the later 2009+ V8 S5 coupes. There is the one big upper intake manifold and then two smaller side intake manifolds with the vacuum operated intake manifold flaps inside. So I applied vacuum to the vacuum nipple of the passenger’s side/right intake manifold and then the flap moved out of place.


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This was the best picture that I could get of the intake valve somewhere along the passenger’s side of the cylinder head. It has a decent amount of carbon buildup with just over 26K miles. There is a small chunk on the valve stem starting to appear. I don’t know which valve and port it is because I had no idea where the camera probe went once it was past the throttle body. The only way that I can tell that it is one of the passenger’s side intake valve and port is because I tried moving the intake manifold flaps on the driver’s side and the flap on my camera probe screen wouldn’t move.


http://i284.photobucket.com/albums/ll37/Jimmybones777/BK560008_zpsadfn4gyl.jpg

Definitely not the highest quality pictures from the camera probe but that is to be expected. Hope that this helps clear up a few things.

#2

Thanks for not only taking the time to look, but also documenting and sharing with everyone!

  • rep!

Any recommended intervals for carbon cleaning? I’m close to 30k miles so should be around the same as your buddy’s RS5.

#3

Good stuff. Pretty cool to see.

Jimmy, ever think of starting a business? Like a legit Jimmy’s garage with a sign and everything? You seem to really like this stuff, and that always makes for excellent business when the owner loves it.

#4

PsYkHoTiK, At this point I have been using my camera so much that it isn’t a big deal.

Thank you for the Karma.

If it were me then I would do a carbon clean every 30-40K miles on a RS5. Recently I have had an experience with a V8 S5 where the carbon buildup caused other issues so I would clean it out sooner rather than later. I am working on posting about that S5 in my Jimmy’s Garage thread but there are over 300 pictures that I have to sort through first. Also I want to try something on this RS5 to reduce the carbon buildup after looking at the JHM SC kit that I have on my B6 S4 but I will keep that to myself until I make sure that it works. It is extremely easy to get to the PCV valves on the RS5 so it makes the perfect test car.

Saki, I own a small entertainment company with three employees because there is not enough profit margin to do mechanical repairs for a living in this area where I live. Typically I am really shrewd with my money so I have looked at doing mechanical repairs from both the owner’s and tech’s/employee’s view points. As a shop owner the operating costs (rent, utilities, employees) are outrageous and I don’t trust most techs in the area to produce at my level of expectations. As a tech/employee of a local shop there isn’t enough work to earn a comfortable living regardless of how much the shop is willing to pay per hour (commission or hourly). I do miss working on cars for a living a lot and it would be nice to get back to a regular work schedule again. To be totally honest, if I were to work on cars for a living then I would move to somewhere warmer. I am tired of winter and would love to move to somewhere where it stays warm year round.

#5

I dropped off my car at Achtuning for an oil change (30k miles) and asked that they do a carbon cleaning as well (mainly since I’m very curious).

Was curious since I drive the car like it should (redlined daily from day one) and it sees track use just how bad it would be. And well, it’s there alright lol.

http://images.tapatalk-cdn.com/15/12/09/bf5847f0e602ce063f308293e69c919e.jpg

Pic courtesy of Achtuning.

They’ll be doing a good cleaning of it (walnut shell).

Figured I’d report back since they took the manifold off. :slight_smile:

#6

Very interesting and thank you for sharing!

When I get a RS5, I am going to do a carbon clean and get the injectors cleaned/rebuilt/flow matched right away. It just makes sense to me after seeing all the RS4 guys having issues with the fuel injectors and after fixing that white B8 S5 V8 Coupe that is in my Jimmy’s Garage thread. Maybe I can sell my buddy on the idea at 28K miles/due for the next oil change.

As a side note, the maintenance on a RS5 is pretty extensive. Engine air filters get replaced along with the manual S-tronic fluid gets flushed every 20K miles past the first 15K miles. Then the rear sport diff fluids get changed every 40K miles after the first 35K miles. That is in addition to the normal oil + filter change every 10K, pollen filter change every 20K (past first 15K), and spark plugs at 55K miles.

#7

That’s a great point about the injectors. I’ll ask how they look. Thanks!

#8

I would also tell them to leave the port dividers out too. A lot of people including me have done that on multiple FSI engines with no weird issues or problems. It seems to make the flaps move easier too.

#9

Any beits of leaving them on/off? Out of curiosity. Uncharted territory for me (but would really love to learn more). :slight_smile:

#10

Sorry it took so long for me to get back about this. The flaps and port dividers intentionally cause turbulence so that the engine makes more low end torque but in my opinion they also restrict the high end horsepower too. With the port dividers out of the way then the flaps move over anyways and still cause turbulence. The RS5 needs everything it can get air wise above 4K rpms anyways so I would pull the port dividers and never look back.