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Hello everyone. My name is Mert. I'm a fellow board member (recently posted pictures of my car), enthusiast, and also a BMW Master technician. Thought I would share some pictures I took at the dealer concerning the SECONDARY AIR SYSTEM CARBON BUILD UP. This is not a DIY thread, but more of an understanding of the procedure. I cannot give out any information about this vehicle but to let you know this is a E39 M5.

carbon build up does not affect just the secondary air system but also the combustion chamber









exhaust valvetrain





secondary air entry port





rear of the cylinder head with the secondary air port freeze plug drilled out and ready for removal. there are three freeze plugs for the secondary air passages that need to be removed and ports cleaned out



rear freeze plug (#1) removed. pictures show cylinder head upside down on cylinder head stand to perform procedure



special cleaning tool (looks like a rifle barrel cleanng rod). Tool is used with a drill and passed through the secondary air main port.





halfway through the secondary air main port, we hit solid carbon. Let me be the one to tell you, it's like hitting solid metal. Took some time to get though it but we did



after cleaning out main port




this is the front of the cylinder head showing the entry of the main port and also the front main port freeze plug (#2). When looking at the front of the cylinder head, the secondary air pump pumps air into the main port entry of the head then immediately makes a 90 degree turn through a short passage way in the front of the head then makes another 90 degree turn and through to the back of the cylinder head into smaller individual ports to each exhaust valve port



this is the freeze plug (#3) that goes from the entry port through the short passage port to the main port



side view of head showing route of air passage



the smaller individual secondary air ports to each exahaust valve port. the right port in the picture looks to be unclogged, but is clogged about halfway through



removal of carbon with reaming tool and then bristle tool





left port after procedure. you can see the difference in diameter



both ports after procedure



all exhaust valve air ports cleaned out



both cylinder heads are being sent out for further cleaning and inspection. this would be the perfect time to get any cylinder head performance work done.

Hope this helps out.

Mert
 

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Excellent pics! Do you have any idea what the dealer charged the customer for this work? That carbon build up is really bad! I have the same problem and I shudder at the thought of what my engine looks like! BMW really screwed up on this design big time.
 

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Wow, what pictures!
What a job!
In a nutshell, what causes this problem? bad fuel? Excessive idling? What?

Neil
 

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Are all e39 M5's affected or just the US spec ones ?

Must be very satisfying when you put it all back together and start the engine :applause:
 

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Fantastic post! Thanks for the clear pictures of the secondary air issue as it is much easier to understand now. Given that the ONLY purpose for the secondary air system is cold start emissions, I'm guessing Powerchip is going to be reeling in some income as E39 M5s age. :)

Thanks again for such great pictures and description.

Chuck
 

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Great post.

Gustav - could you consider adding this to the CBU FAQ?
 

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So from now on, when some one says they fixed their carbon build up with a power-chip, all they did was get the code permanently erased. I hate when people who are selling m5's say " Carbon build-up fixed with power-chip"
 

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The inside of that engine looks horrible. To think mine looks similar just makes me cringe. Not what I needed to see since I'm getting ready to put a new suspension in, new wheel bearings and new p/s lines.
 

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What is the mileage on this motor?
 

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So from now on, when some one says they fixed their carbon build up with a power-chip, all they did was get the code permanently erased. I hate when people who are selling m5's say " Carbon build-up fixed with power-chip"
It's a con isn't it?

It's like covering your eyes and believing what's in front of you doesn't exist..
 

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thanks for the pics, that is some big time buildup on the pistons, i've opened motors with over 200k miles that have been punished and didn't look anything like that.
 

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It's a con only if Powerchip didn't tell you what they were doing. They do, so no it's not a con. It doesn't "fix" the carbon buildup, it only keeps the CEL from lighting so the car will pass inspection. From what I've read the cleaning procedure will cost big bucks. And then it could happen again.

Powerchip is a solution, not an actual fix.
 

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I dont understand how you guys can call Powerchip a con. Its a very sensible solution given that the only other option is spending $8k for BMW to clean it out or at least half that with any indy shop. Let's not forget, as stated earlier, this problem could come back.

Looking at this engine, there seems to be more carbon buildup on the pistons than normal compared to other s62 engines I have seen.
 

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great pictures and post Mert. I'm also curious how many miles were on this car. I can post some pics tonight of my car at 72k miles when the heads came off, it was much cleaner, wrt carbon. (heads were coming off for other reasons.)
 
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