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      04-16-2012, 04:13 AM   #15
Dackelone
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Drives: N54 e82
Join Date: Feb 2010
Location: Bayern, Germany

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Quote:
Originally Posted by DriveHard View Post
BMW does not consider the cleaning of the valves as a Maintenance or Warranty matter, although it has been done in extreme cases..

Having BMW do it as a preventive measure, in my opinion will not happen..

BMW has devised a Special tool / Equipment / procedure when a dealer does do it..

First it does require the removal of the intake manifold. The special tool sucks and blows at the same time thre a special fitting that fits tightly over the intake port.. A vacuum is applied to the fitting and there is a small port that allows a wand to enter the fitting and spray the valves with the walnut shells.

The cylinders have to be at TDC when doing so. There is no chance of getting shells in the combustion chamber. The port has to be thorougly cleaned after removal of the special fitting.

It is very time consuming ( about 3+ hours to do 6 cylinders. )

The media that BMW specified is special.. It is very fine. I dont know how it compares to stuff you get on the outside..

Forget about "ordering" the tool from BMW $$$$ wise... especially if one is doing it "just in case"


A personal note: the build up happens more to what one would call "station" cars... meaning very short trips / start stops / etc.. Cars that have been.....well lets say...Driven Hard ( pun intended) dont seem to suffer as much.. I also feel that this is in inherent design flaw. ( for all manufacturers )

The simple fact that the valve stem is HOT and lubricated leads itself open for accumulation over time.. The carbon build up is simply the oil used to lubricate the valve stem and also the residual oil that circulates thru the intake manifold thru the crank case vent valves (aka PCV valves for us old timers)

There are more failures of Crank case vent valves then i care to count.


I dont think this is one of those good / easy DIY's my .02

Regards,

Alex

Thanks for the info AND for posting this!


So... just bc I am the curious type.... How does one know when your crankcase vent goes bad?

Dack
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