[robnitro]

I recently removed the swirl flaps as a preventative measure on my x5 35d. It had 110k when I bought her, presumably mostly highway from the location it was registered and it is a 2011.

The egr was very clean but it did have the egr recall done.
There was a thin layer of soot around the round ports, where flow goes at low load (high egr rate). The rectangular ports were very clean. The flaps had wear on the seal and some were weeping oil. Most of the flaps had build up on the backside, probably from times of partial opening.

I think the condition was good only because of mostly highway and the x5 using less hp egr due to the lp egr. A big middle finger to bmw for not putting a temperature gauge, I'm sure like my thermostat was starting to go, many are running too cool, speeding up cbu.

On my previous car, a 01 vw tdi, I did the cleaning at 70k and was the egr, intake, and ports were horrible, very similar to the pictures shown of the 335d.

It was said on tdiclub that the euro cars get less build up. 2 variables here: the fuel is better, and they didn't have egr coolers. An egr cooler adds to the condensation effect of oily vapor.

Where people had catch cans or elephant ccv (to atmosphere) soot still accumulated but at a much slower rate and it was much easier to scrape off.

I fitted my old eclipse ccv filter on my 35d and plan to run a good 0w40 or 5w40 that vaporizes less (lower noack %) than this LL04 crap.

[Nadir Point]

Originally Posted by robnitro

I fitted my old eclipse ccv filter on my 35d and plan to run a good 0w40 or 5w40 that vaporizes less (lower noack %) than this LL04 crap.

I postulate the excessive vaporization contributing to CBU is regen-induced fuel dilution. My car consistently returns fuel dilution rates in the 4-6% range. I started doing partial 2qt. oil changes every 3k miles 3 years ago after discovering the problem. BMW declined to explain it when the issue continued, even after new injectors. Can't wait to get the deletes/tune done, oil changed and see what the next analysis says.

Only 4 weeks to go...

[robnitro]

What about the post injection used for the stored up of warm up? I have a 25 minute stop and go commute right now and am worried about the upcoming winter. I may build a coolant heater pipe using 3 tdi 12v glow plugs, a 60 amp relay and a simple contact thermo switch to help heat up coolant like the tdi manuals had.

[lnxguy]

Originally Posted by robnitro

What about the post injection used for the stored up of warm up? I have a 25 minute stop and go commute right now and am worried about the upcoming winter. I may build a coolant heater pipe using 3 tdi 12v glow plugs, a 60 amp relay and a simple contact thermo switch to help heat up coolant like the tdi manuals had.

You think the M57 will have a hard time heating up like the TDIs did? I've been wondering the same as I haven't heard of anyone running a coolant heater (Like most of us did when running TDI's in cold climates)

[Nadir Point]

Originally Posted by robnitro

What about the post injection used for the stored up of warm up?

There are several factors contributing to CBU and I'm sure that's one of them, but regen has to be the biggest. Our climate in CO is on the warm side, generally speaking, and my car has seen predominately highway miles up until just recently. The scenario I described with my particular car points to DPF regen as the biggest factor, by far. That's why I'm characterizing regen-induced fuel dilution in the crankcase as the root cause. It's the foundation on which CBU is built.

[robnitro]

Originally Posted by UberArchetype

There are several factors contributing to CBU and I'm sure that's one of them, but regen has to be the biggest. Our climate in CO is on the warm side, generally speaking, and my car has seen predominately highway miles up until just recently. The scenario I described with my particular car points to DPF regen as the biggest factor, by far. That's why I'm characterizing regen-induced fuel dilution in the crankcase as the root cause. It's the foundation on which CBU is built.

Good point!
Also when the engine is cold, there is little vaporized oil!

Originally Posted by lnxguy

You think the M57 will have a hard time heating up like the TDIs did? I've been wondering the same as I haven't heard of anyone running a coolant heater (Like most of us did when running TDI's in cold climates)

Not sure, but my stop and go idling commute doesn't put much heat into the engine until I get past the traffic. I plan to tap by the oil cooler, drill and tap a few holes in a piece of pipe and put 3 regular glow plugs (I don't have the coolant TDI ones anymore and they are much more expensive!).