Carbon Build Up 35d swirl flaps intake manifold M57 with pics

[ZetaTre]

Subscribing as I'm very interested in the picture.

You've probably read it elsewhere, but my theory about CBU is that is the result of very poor control of the amount of oil that gets into the intake through the crankcase ventilation system. This theory comes from the simple observation that if soot alone was the cause, you'd have build up in the EGR cooler, not only the intake. Instead, the residues in the EGR cooler are light and can be easily wiped away while the intake is covered with tar.

Goes without saying that if you remove the soot (by modifying the EGR), you remove 50% of the problem: that's perhaps the reason why the X5 thanks to the LP EGR have less CBU problems.

I actually went the other way and removed the oil from the PCV by installing a ProVent 200 separator that drains the oil back to the sump through the dipstick. Here's my whole endeavor: http://www.xoutpost.com/bmw-sav-foru...separator.html

Not too long ago I cleaned the intake using the Liqui Moly Intake Cleaner. Provided that I have not remove the whole intake yet, when I recently removed the charge pipe it's clear that the EGR valve now has very minor buildup on it and the intake is absolutely dry, there's no oil film on anything and the oil level in the sump remains absolutely the same between oil changes (compared to a shortage of roughly 1qt every 5K miles).

I'll bet you that when you removed your charge pipe you had a little puddle of oil right in front of the flap.

I'm about 3K miles away from next oil change at which point I'm probably gonna update the thread with some pictures. I made it a point to use the Liqui Moly again as a way to slowly clean off what has built up before the ProVent. That stuff is no magic cleaner, but it does melts off the tar from the intake...

PS: you actually got the ports a bit confused. There's a tangential port and a swirl port. The tangential is rectangular and the swirl is round. The flap on the tangential is called "swirl flap" because it closes the tangential and forces the air through the swirl.

Consider the swirl flap open to allow air through the tangential ports under higher engine speed; in general this means that most of the time the swirl flaps are closed. Also higher engine speeds most often come along with higher engine loads in which case makes it more likely for the EGR to be closed. That's likely why your tangential ports are cleaner than the swirl: they are used less and when they are used there's less soot in the air.

[sgrice]

Hopefully everyone can see the pics now. Sorry for not having them properly up initially.

Pierce330: My car is roughly 5 years and 4 months old, with roughly 80,000 miles. So that averages to about 15,000 miles per year. Daily commute to work is roughly 20 miles each way, of which about 15 is highway.

ZetaTre: Excellent deductions, Sherlock! I did in fact have a small puddle of oil in the throttle body when the charge pipe was removed, as you predicted. Also, just as you say, the EGR cooler itself only has very light residue (like the tangential intake port). I think you are correct with your ideas and effort on the ProVent. And thank you for correcting me about the terms for the different ports - I have edited my original post and hopefully have it correct now. And your thought about why the tangential intake port is so clean is spot on, I suspect.

Regards.

[ZetaTre]

Originally Posted by sgrice

Hopefully everyone can see the pics now. Sorry for not having them properly up initially.

Pierce330: My car is roughly 5 years and 4 months old, with roughly 80,000 miles. So that averages to about 15,000 miles per year. Daily commute to work is roughly 20 miles each way, of which about 15 is highway.

ZetaTre: Excellent deductions, Sherlock! I did in fact have a small puddle of oil in the throttle body when the charge pipe was removed, as you predicted. Also, just as you say, the EGR cooler itself only has very light residue (like the tangential intake port). I think you are correct with your ideas and effort on the ProVent. And thank you for correcting me about the terms for the different ports - I have edited my original post and hopefully have it correct now. And your thought about why the tangential intake port is so clean is spot on, I suspect.

Regards.

That is fantastic!!!!! Thanks so much for posting this!

I did try to sneak a borescope in the intake on mine, but I couldn't get to the valves.

Btw, how were the overall condition of the swirl flaps? You probably read about problems with earlier M57 models where they would come loose and drop in the intake. The story has it that our version of the M57 has no such problem. Did they feel solid? Any play in the shaft?

Again, great post!!!!!

[sgrice]

The swirl flaps felt very solid. They opened and closed very smoothly. No play at all in the shaft. Rubber gasket areas all solid. So apparently the design changes were successful!

[ninja_zx11]

Excellent post by you sgrice!!!Thank you for sharing your work....

I will be doing this while changing glow plugs on mine as i need to remove the intake.

[ChuckG]

Originally Posted by ninja_zx11

I will be doing this while changing glow plugs on mine as i need to remove the intake.

Why are you changing the glow plugs? Unless you have a failure there is really no reason to change them. If one fails the engine will run just fine. The glow plugs are just used when starting. One cylinder with the bad glow plug will fire OK after the rest of the engine starts up and run. I had one glow plug fail because its power supply had too high of voltage that burned it out. The only indication was a check engine light. The engine ran well with the glow plug burned out.

Chuck

[ZetaTre]

Originally Posted by ChuckG

Why are you changing the glow plugs? Unless you have a failure there is really no reason to change them. If one fails the engine will run just fine. The glow plugs are just used when starting. One cylinder with the bad glow plug will fire OK after the rest of the engine starts up and run. I had one glow plug fail because its power supply had too high of voltage that burned it out. The only indication was a check engine light. The engine ran well with the glow plug burned out.

Chuck

That's not true in our car. Glow plugs are also used under light load when the coolant temperature is below 75C. Below that temperature the DDE enriches the mixture to accelerate warmup and uses the glow plugs to improve combustion and reduce soot that would otherwise result from the richer mixture.

When the thermostat fails (as in ninja's case) the engine runs cooler too long or in some cases doesn't even go above 75C which results in extra duty for the glow plugs that burns out. This (the temperature dropping as a result of a failing thermostat) is particularly true when there's a light load which is a precondition for the use of glow plugs

[ninja_zx11]

Originally Posted by ChuckG

Why are you changing the glow plugs? Unless you have a failure there is really no reason to change them. If one fails the engine will run just fine. The glow plugs are just used when starting. One cylinder with the bad glow plug will fire OK after the rest of the engine starts up and run. I had one glow plug fail because its power supply had too high of voltage that burned it out. The only indication was a check engine light. The engine ran well with the glow plug burned out.

Chuck

because cylinder 3 glow plug failed and having check engine light on.Code 4A4E(glow plug open circuit).I think exactly what happened as ZetaTre said.It starts OK but sometimes i get little rough idle for first 3-4 secs.

[split71]

Originally Posted by ZetaTre

Subscribing as I'm very interested in the picture.

You've probably read it elsewhere, but my theory about CBU is that is the result of very poor control of the amount of oil that gets into the intake through the crankcase ventilation system. This theory comes from the simple observation that if soot alone was the cause, you'd have build up in the EGR cooler, not only the intake. Instead, the residues in the EGR cooler are light and can be easily wiped away while the intake is covered with tar.

Goes without saying that if you remove the soot (by modifying the EGR), you remove 50% of the problem: that's perhaps the reason why the X5 thanks to the LP EGR have less CBU problems.

I actually went the other way and removed the oil from the PCV by installing a ProVent 200 separator that drains the oil back to the sump through the dipstick. Here's my whole endeavor: http://www.xoutpost.com/bmw-sav-foru...separator.html

Not too long ago I cleaned the intake using the Liqui Moly Intake Cleaner. Provided that I have not remove the whole intake yet, when I recently removed the charge pipe it's clear that the EGR valve now has very minor buildup on it and the intake is absolutely dry, there's no oil film on anything and the oil level in the sump remains absolutely the same between oil changes (compared to a shortage of roughly 1qt every 5K miles).

I'll bet you that when you removed your charge pipe you had a little puddle of oil right in front of the flap.

I'm about 3K miles away from next oil change at which point I'm probably gonna update the thread with some pictures. I made it a point to use the Liqui Moly again as a way to slowly clean off what has built up before the ProVent. That stuff is no magic cleaner, but it does melts off the tar from the intake...

PS: you actually got the ports a bit confused. There's a tangential port and a swirl port. The tangential is rectangular and the swirl is round. The flap on the tangential is called "swirl flap" because it closes the tangential and forces the air through the swirl.

Consider the swirl flap open to allow air through the tangential ports under higher engine speed; in general this means that most of the time the swirl flaps are closed. Also higher engine speeds most often come along with higher engine loads in which case makes it more likely for the EGR to be closed. That's likely why your tangential ports are cleaner than the swirl: they are used less and when they are used there's less soot in the air.

ZetaTre, I read your thread on improving the CCV system. It looks like both you and the OP have a bit of oil blow-by. With the lack of a good CCV, I think this accelerates the CBU issue.

The question I have, how may members with CBU issues were also using 1 or more qts. of oil between oil changes? Probably should start a thread on oil usage and CBU....

[ZetaTre]

Originally Posted by split71

The question I have, how may members with CBU issues were also using 1 or more qts. of oil between oil changes? Probaly should start a thread on oil usage and CBU....

You could, but it's very rare. I've read of 1 X5 diesel diagnosed with CBU, while is more common in the 335d.

You can check the Diesel section of the other forum that has a Diesel section, but mind you that once you cross that door and enter that world (the Diesel section is it's own world of that forum) you'll be greeted by a group that is a cross of doomsday preppers, medievil flagellants, and alcoholics anonymous.

So make sure you use their greeting: "Hello my name is [...] and I have carbon buildup" or you would be ignored and called an infidel...

And btw, it is entertaining to read... Very entertaining...