[capt_slow]

When I started the car this morning, I noticed a faint vibration coming from the engine. It's almost a faint jolt that occurs once every 2-3 seconds and goes away once the engine is warm. I took a look underneath the hood and couldnt find what was causing it, but did spot a oil leak coming from the air outlet tube.

There's oil build up on one of the hoses that go into the 13-71-8-574-783 air outlet tube, which appears to lead into the cold side of the turbo.





It's connected to the oil fill reservoir. Has anyone experienced either the leak or the vibration before?

The car just had a oil change and this spot is near the fill cap. So I'm hoping the tech was just sloppy and spilled oil all over the place.

[capt_slow]

I may have found the problem. That's the engine breather tube. I checked the oil level after the car was sat overnight and it looks overfilled:



The last oil change was done by the dealer 264 miles ago. I'm guessing they overfilled it.

[FaRKle!]

The hose covered in oil residue is the ccv hose that recirculates blow by into the intake. It's normal to have that amount of residue on the outside of it. The OE clamps holding the corrugated hose to the heating element don't have a very tight/secure grip.

[capt_slow]

Originally Posted by FaRKle!

The hose covered in oil residue is the ccv hose that recirculates blow by into the intake. It's normal to have that amount of residue on the outside of it. The OE clamps holding the corrugated hose to the heating element don't have a very tight/secure grip.

That's good to know. I opened up the air filter and thankfully the insides are clean. Probably take it back to the dealer anyway for them to drain some oil out, and for another ride in that M340i loaner

[eugene89us]

I agree with the message above. Mine gets covered with thin residue over about a year. It is a part of my usual under the hood cleaning each year, as I wipe pollen, remove leaves, and clean off the oily residue. My dealer overfilled my oil each and every time, but thankfully I am done with my "free" oil changes, so I will fill it right by checking with a dipstick.

As it comes to your vibration question, I have had a few posts on this forum with similar concerns. Sometimes my engine does not idle consistently. Since dealer raised my idle RPM by 10, the tach needle has been stable (in the past, it would vary by 10-20 rpm at times). But I can still sometimes hear surging idle when I come to stop for about 5-10 seconds before idle normalizes. Sometimes there is very low perception of slight side to side jolt, you have to be very still to perceive it and sometimes I feel it is just in my head. Other folks have experiences similar symptoms of surging idle on these N47T engines, so I thinking it is by design. I had BMW NA involved and they reviewed by FASTA data to determine everything is working to spec. My cousin, who is an engine mechanic, says it is quite typical for high efficiency diesels to be programmed this way, they prioritize economy over comfort, and especially during winter season tend to run rougher on winter blended diesel fuels. I tested everything with ISTA, from intake, MAF, injectors, fuel system, etc - everything passes the test. So I have accepted this to be normal.

[Enabled]

It only seems that the later 328d have a surging idle?

I spent about a week at 8,000-10,000+ feet altitude at way below freezing with my wagon and it was always buttery smooth and solid idle.

[eugene89us]

Originally Posted by Enabled

It only seems that the later 328d have a surging idle?

I spent about a week at 8,000-10,000+ feet altitude at way below freezing with my wagon and it was always buttery smooth and solid idle.

It sure seems that way. We are right about sea level here in Mississippi. I think the engine raises its rpm in higher altitudes to account for "thinner air". What I found interesting is the thread that talked about people's idle RPM, seems different folks have different RPM depending on their location. I wish they were more scientific with pulling up secret menu and defining digital RPM reading, since it is not precise to evaluate RPM by tach needle alone. But it was still peculiar that some had theirs in 600s and others in 800s.

When I raised it from 770 to 780 at idle, you could barely see the change on tach but it ran smoother. I want to try to raise it to 800 rpm on idle to see if that does the trick. The thing is, this rough idle does not translate into any issues when accelerating. When RPM was at 770, it would seem the engine would struggle to keep up at idle with all accessories running. Turning off AC would smooth the ride, as if engine was being overworked. Since RPM increase by mere 10, no more tach needle movement. Just 5 seconds or 10 seconds of surging sound only before it smooths out. I will raise it by another 10 and report back. Not like that would affect my fuel economy, I generally idle once to twice a day if I catch a red light, the rest is interstate driving.

[Enabled]

Here is the idle rpm data from the 328d ecu flash, these are identical for LCI and for non LCI. (note, this is the data unmodified by ISTA rpm adaptation edits)



Mine runs very smooth at all those indicated values. Sea level is at a perfect 780.


FWIW, the X3 28d has the 780 values as 810rpm instead.

[capt_slow]

The dealer ended up replacing the hose, but couldnt find much about the cold start problem.

As for the oil level, they confirmed that the dipstick read overfilled. Drained the engine oil, confirmed proper amount came out, and put the same oil back in.

[eugene89us]

That is pretty nice info, follows what you'd expect - higher RPM in higher altitude (thin) air or at lower temperature (I presume to help engine warm up quicker). Mine was 770 by default, which is why I think it was struggling. Our air pressure here is 1025 mbar today, it is usually around upper 900s-1000s here, so raising it to 780 at idle was definitely a right thing to do as car no longer vibrates unevenly or struggle. Of course, diesels vibrate a lot, but as long as it is a consistent vibration, I am happy. When it starts surging or shaking, this bothers me a lot.

[Enabled]

I wonder why someone lowered it to begin with, if that's what happened

That would have been done through ISTA adaptation addition or subtraction.

780 should run right. 790-800 wouldn't be bad either.

[eugene89us]

Originally Posted by Enabled

I wonder why someone lowered it to begin with, if that's what happened

That would have been done through ISTA adaptation addition or subtraction.

780 should run right. 790-800 wouldn't be bad either.

Brand new car when purchased, had 13 miles on ODO when I got it. Unsure if false adaptation or something. Started making sound around 5K to 10K miles, started to vibrate at 30K. Once RPM lifted, no vibration and currently at 35K. Documented by the dealer, so if this turns into something, I have some ammunition to pursue BMWNA coverage (maybe?).