Originally Posted by ninja_zx11 (Post 1029518)

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

Originally Posted by ChuckG (Post 1029575)

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

Originally Posted by ChuckG (Post 1029575)

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

Originally Posted by sgrice (Post 1029401)

I'll be honest and say that my car doesn't seem to be running any differently now - so maybe all my efforts were for naught. But I doubt it - I think that eventually my swirl flaps would have become stuck, with subsequent check engine lights (CELs) and various codes. I keep telling myself that I saved myself from an inopportune future mechanical issue, but who really knows?

Originally Posted by ZetaTre (Post 1029480)

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.

Originally Posted by split71 (Post 1030333)

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....