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

[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...

[BMWagon]

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.

Hi @ZetaTre. I have a perhaps trivial question, but how do you apply the LiquiMoly cleaner? I just finished cleaning my intake on a 2009 X5 with roughly 74K miles (thanks PO for this write up as well as the other one that describes how to remove intake manifold). The cleaner has to be applied when the engine is running. It needs to be introduced into intake track and my question is how do you do that? If you remove the charge pipe that goes into TB you are going to mess up the air flow as this will introduce extra air passed the air flow meter. I have not dared to do so but I'm assuming the car will immediately start running rough. Am I mistaken?

[josiahg52]

Fantastic post. As an owner of a 35d, these posts are very interesting and helpful to me.

[JGard]

Agreed with all the above. I just picked mine up and it's got 60k miles. While I have no reason to believe there's a ton of CBU, that's exactly how it gets you. So some time this spring/summer when I feel like I need a project, I'll definitely be opening things up to clean them out.

[Price]

Originally Posted by sgrice

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?

Have you noticed any change in mileage?

Anyway, great write up!

[split71]

To the OP does your car burn oil? If so, at what rate?

[sgrice]

To Price: Honestly, I haven't noticed any change in mileage after the CBU cleaning. As mentioned on the thermostat thread, I did get a nice improvement in mpg after installing a new thermostat. But nothing that I noticed after the CBU buildup.

To Split71: I would say not really. I have been able to go the roughly 11,000 miles or so between oil changes without having to add any. Though by the time 11,000 miles or so is up I seem to be down about a quart.

Regards.

[blue dragon]

Do you have the workshop manual for removing the intake manifold? Your pictures help greatly, but I just want to ensure I have everything covered. I'm going to change out the glow plugs.

[sgrice]

Blue Dragon - sorry, but I don't have a workshop manual. Be aware that this posting deals more with cleaning up the intake manifold and the swirl flaps. I assume you saw the other diy post I made about removing the intake manifold? That link is here: http://www.xoutpost.com/bmw-sav-foru...ml#post1030289

For some reason the images from Realoem that I had included in several of my earlier posts were not showing up. It seems as if the Realoem web site has changed some of its pages, and perhaps the linked images were unobtainable by the Xoutpost forum (URL not found syndrome). I just now went back and re-added Realoem images. So you might want to check out the link above to see if things are more logical and understandable now.

Perhaps somebody else can chime in with how to get an online workshop manual (I've seen Rheingold mentioned a lot), but I don't know how to download or access it.

[blue dragon]

Thanks, I appreciate you updating the post. Realoem has changed a bit, so I can see how the deadlinks happen