BinsuJiro

There are many very good articles on how to clean carbonized oil deposits from the INTAKE PORTS, VALVES AND VALVE STEMS here in the forum.

But, upon removing the PLASTIC UPPER INTAKE MANIFOLD [06E 133 210 P], I noticed a coating of carbonized oil deposits on the inner walls of the exit ports of the manifold. Clearly carbon is building up in the PLASTIC UPPER INTAKE MANIFOLD [06E 133 210 P] and in the portions of the plastic part that extend below the exit ports.

The problem that I see with this condition is that the buildup is a perfect surface for additional carbon to deposit form and build up as oil finds a rough surface that it adheres to, and the air flow into the intake ports is altered by the rough surface.

Additionally, this condition has the potential to increase the already serious problem of carbon buildup in the intake ports of the heads and on the underside and stems of the intake valves. With direct injection there is no natural opportunity for these deposits to be chemically removed in the normal operation of the vehicle.

BASICALLY, I BELIEVE THAT THIS CONDITION AND THE RESULTING FAILURE OF VALVES AND THE CRIPPLING OF CYLINDERS BY CARBON IS A DESIGN DEFECT. IT IS MY OPINION THAT AUDI SHOULD BE RESPONSIBLE FOR EVERY REPAIR THAT RESULTS FROM THIS CONDITION, AND THAT AUDI OWNERS SHOULD BE PRESSING FOR A PERMANENT REMEDY TO THIS SITUATION AT AUDI'S EXPENSE.

However, my question is about cleaning the inside of the PLASTIC UPPER INTAKE MANIFOLD [06E 133 210 P] without damaging it. Unfortunately the part cannot be opened for cleaning and I could find no documentation of the interior design of the part.

Does anyone have a solution to the problem of cleaning the carbon out of the PLASTIC UPPER INTAKE MANIFOLD [06E 133 210 P]?

Thank you,
Vincent

A6Gary

After I did a carbon cleaning of the intake valves and flow diverter plates last year, I used Seafoam cleaner by intaking it slowly thru the EVAP N80 valve outlet line into the upper intake. I did this to try and cleanup the intake passages in the upper intake and catch the leftover debris behind the intake valves. Now I do this cleaning every year right before I change the oil/filter to hopefully minimize the carbon buildup in the intake system. I don't have any objective evidence this prevents the carbon buildup, but it certainly can't hurt. Based on the amount of carbon buildup I observed when I disassembled the intake system to replace a failed driver's side lower intake vacuum actuator @ 80K miles, I think this preventative maintenance will keep the carbon buildup problem in check.

BinsuJiro

A6Gary,

Thanks for the suggestion. Is the engine running when you do this, and how does it affect the combustion and Catalytic converters? Or, do you disassemble the upper intake to do any of this preventive maintenance?

LarryJa

I just completed my "summer maintenance" on my '06 A6 3.2.
That included using Seafoam Spray top engine cleaner & lube. You run it into your air intake, ahead of the throttle body. You run the engine up at about 1500-2000rpm, & spray it in.
I suspect that it staturates & cleans the throttle body, manifold, ports & valves somewhat.
I do it annually, & it improves the idle, as well as throttle response. So, I'd say it is relatively effective, considering that it only costs about $10 & 15min of my time.
It's not a replacement for a thorough manual carbon cleaning, but it seems to do it's job.

A6Gary

I run the Seafoam thru plastic tube that has a air pump needle on the end to SLOWLY suck the liquid into the manifold at idle speed. I pour the Seafoam into a plastic cup, and use that as the supply (not directly out of the can. Using this method, I can control the amount of the Seafoam into the manifold. After I run a can thru the intake, I rev up and hold the engine speed for a minute or two to fully clean out the intake and combustion chambers. I then connect my VCDS to clear the DTCs in the engine module (e.g., rich mixture, misfires, etc.). If you SFTAs, you should find a post about this method that some else posted.