Audi RS5 B8 Oil catch can

Hi guys.

Over the weekend I bought some CRC cleaner and I am just waiting for that to arrive so I could have a little go in helping to minimize the carbon build up like what ape factory did that video was really helpful btw!.

Was just doing abit of research as well about having an oil catch can to help with the prevention of the carbon build up these 4.2 V8 FSI engines are known for.

Was just wondering has any of the members fitted one and if possible be able to guide me on how to fit one in what equipment and materials do I need? As I can’t find anyone who has fitted one online. Can only find like the Audi S5 4.2V8 but then the pcv intake system is a different layout to the RS5, and the RS5 doesn’t have as much room either so where would be the best place to place one?

Be much appreciated for your help.


I’m working on designing one actually but here’s the thing…the carbon buildup comes not only from volatiles in the intake path (via the PCV) but also through oil leakage on the valve guides in the head and valve overlap when there’s a bit of blowback from the combustion cycle. Even though the intake valves would be seriously hot to the touch, they’re far cooler than the combustion gasses so they accumulate quite readily on the much colder (relatively!) valves.

But…If you can remove more volatiles from the intake tract, has to help a bit. It won’t eliminate carbon buildup though.

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Yes, the PCV valve design on the RS5 is very different from that on the S5 and it seems that with properly working PCV valves should suck most of it past the valves and into the combustion chambers.

For that reason, I am not sure I would personally put a catch can as the proper flow of the air liquid mixture will help cool the intake a bit and ensure the carbon is blown past: at least in as far as the catch can, depending on design, will trap the liquid which would both help clean and also as mentioned cool the mixture as it turns into steam.

On mine there has been no sign of leaks from the valve seals as there was oily carbon on the walls – the tough shiny/metallic build up almost on the valve heads exclusively. I will personally try to see if using CRC valve clean or similar products will have a preventative effect on the build up (will pull the intake about once a year/10.000 miles and apply the product directly).

If it does not get worse I can live with the slight build up on the heads as long as there is no restrictions before in the air flow it should possible to limit it.

Once again I’d be interested in your finished catch can design !! Keep me up to date on how you get on with this and i know you being you will try and test it very thoroughly before your happy to commit on the finished product and that’s good enough for me !! :+1:

I just secured a source for the OEM fittings earlier in the week. Last thing I need to do is figure out an adapter to go from the new hoses to the PCV hoses using that OEM fitting. Otherwise it’d mean cutting those hoses off altogether and connecting directly to the PCV fitting. I could offer both options as those hoses do crack with time and cause issues.

I’ll also be relaunching the air pump hose relocation kit with OEM fittings. I still have to figure out the final spec but it may actually come in less expensive than the original version which used two very hard to get and rare components.

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Sounds like your on it ! Keep us posted on how things are going and when its ready for release, I’m interested in this anything to keep the carbon build up away or even to slow it down will be beneficial.