Diesel exhaust survey - do I have a problem?

[850man]

Hi folks,

Newbie to this forum and to X5 ownership here with a question for you experienced people out there... I have a 2012 X5 30D equipped with DPF and only has 65,000 Km on the clock. it runs beautifully and I love it but... the exhaust tailpipes have carbon soot in them. It was there when I bought it and I have cleaned it out several times but it just comes back. It's dry not oily. I never see black smoke when accelerating, the engine uses no oil. I asked BMW at the time I bought it and they said it was normal for a car that had done short trips around town and would clean itself up with a few longer trips.

Since then I have covered 5000 Km, my minimum commute is 25Km at 100Kmh and I have done a number of 250Km trips, given it many bursts of full throttle and initiated 3 DPF regens using Rheingold which have all completed successfully.

The exhaust tailpipes still get sooty inside. Is this normal for a BMW diesel? I have seen other that are clean as a whistle. What do you guys think?

[fsd350]

Originally Posted by 850man

Hi folks,

Newbie to this forum and to X5 ownership here with a question for you experienced people out there... I have a 2012 X5 30D equipped with DPF and only has 65,000 Km on the clock. it runs beautifully and I love it but... the exhaust tailpipes have carbon soot in them. It was there when I bought it and I have cleaned it out several times but it just comes back. It's dry not oily. I never see black smoke when accelerating, the engine uses no oil. I asked BMW at the time I bought it and they said it was normal for a car that had done short trips around town and would clean itself up with a few longer trips.

Since then I have covered 5000 Km, my minimum commute is 25Km at 100Kmh and I have done a number of 250Km trips, given it many bursts of full throttle and initiated 3 DPF regens using Rheingold which have all completed successfully.

The exhaust tailpipes still get sooty inside. Is this normal for a BMW diesel? I have seen other that are clean as a whistle. What do you guys think?

Yes it is quite normal on your d. Getting on the go pedal for a long run rather than a burst helps mitigate. 100kmh is only 62mph. Our engines are not working hard at that speed. I know I have a hard time driving any of my Bimmers that slow (haha). Gassers can get carbon around the pipes too, depending on the model and how they are driven. I assume your fuel mileage is ok?

[850man]

I'm averaging 8.3l/100Km (28 US MPG) and often see the needle on about 7l/100Km (34 US MPG) when on a flat road cruising at 100Km/h - is that about right for a 30D?

[Ozer]

34mpg is at the very high range for a diesel so great if youre getting that. The black soot is normal, its a diesel after all.

[fsd350]

Originally Posted by 850man

I'm averaging 8.3l/100Km (28 US MPG) and often see the needle on about 7l/100Km (34 US MPG) when on a flat road cruising at 100Km/h - is that about right for a 30D?

Agree with Ozer, your d is getting great mileage, at the upper end of spectrum for MPG.

[Ozer]

Originally Posted by 850man

I'm averaging 8.3l/100Km (28 US MPG) and often see the needle on about 7l/100Km (34 US MPG) when on a flat road cruising at 100Km/h - is that about right for a 30D?

wait, are you just looking at where the mpg needle is staying as you are driving? If so, thats not accurate. You need to fill your tank, reset the trip and drive till at least 1/4 tank left. Then you fill up again and divide the liters by the number of KM driven to get your true L/Km fuel range.
What does your onboard L/km fuel estimator say you are getting?
Mine is spot on when i do the manual way.

[850man]

The 8.3 l/100Km is the average value in the OBC and when I have checked it by the fill and measure method you describe above, it's been spot on. The 7 l/100Km is using the needle and I agree it's not that accurate.

Sounds like I am worried about nothing with the sooty exhausts although I am tempted to check that the EGR isn't clogged and stuck open because that will lower the temp in the DPF which doesn't help it to burn off soot accumulation.

[ZetaTre]

Your vehicle is different than what's available in the US, where most of the other drivers on this board are from.

More specifically it is not equipped with the SCR system that uses urea and a catalytic reducer to break up NOx.

The SCR system releases in the exhaust big amounts of water vapor both because water is the caring agent of the urea as well from the reaction occurring. I've noticed that SCR equipped vehicle tend to have a spotless exhaust while non-SCR have some, albeit minimal, soot. I suspect the exhaust is effectively "steam cleaned" by the water vapor. I also suspect the exhaust is coated with different corrosion inhibitors.

In addition to that, non-US vehicle tends to be built with less stringent tailpipe emissions. Like it or not, reduction in emission in diesels is accomplished at the expense of fuel consumption. That's why you have significantly better MPG that any US model. The power output of your car is also lower contributing further to the MPG.

One thing I would research is the topic of engine temperature.

Your vehicle should have 2 thermostats: a main thermostat on the engine block and another one on top of the EGR cooler. They both slowly deteriorate and become unable to keep the engine within operating temperature. The on on the EGR cooler is even more problematic.

Hope this helps!

[Ozer]

^ Thats true, totally overlooked the fact he is not in the US hence not having the restrictive exhaust. Good catch!