Help! Why would an ML400 CDI smoke!? - PeachParts Mercedes-Benz Forum

kayooh · #1 10-03-2004, 08:54 PM

Greetings folks,

Right now I am considering the purchase of either a 2002 BMW X5 3.0d (137,000 KM) or a 2003 MB ML 400CDI (73,000 KM).

I am of course leaning towards the MB because I am hoping that bringing it into the country maybe a bit easier (hopefully a lot !!

)than the BMW and of course the extra grunt is always welcomed.

Anyway, the salesman has set me up for a test drive of both but warned me not to get overly concerned with the smoke coming from the tail pipe of the MB as the MB Diesel is a " well known smoker!!" as he has put it.

He continued to add that the BMW unlike the MB is a much refined vehicle and engine and that I should be much better off with it!!

So here is my question, is it possible at this day and age that BMW can produce a smokeless diesel engine while MB can't!! Add to that the BMW is theoretically a year older!

I also took into account the fact that I have not seen what he meant by smoke but nonetheless according to him the MB smokes while the BMW does not.

Can any of you shed some light on what may make this particular engine smoke at all? A misadjusted/defective electronic part perhaps? A clogged filter here or there? Is there such a thing as a "wrong diesel"?? As the salesman mentioned that once.

Any advice is appreciated and thank you all.

AusMBtech · #2 10-04-2004, 06:26 AM

All diesels will generate smoke. It just depends how much. The higher the sulfer contect in the fuel or the poorer the quality of the fuel the more it will smoke.

I don't have any experience with the 400CDI but on the 270CDI I've seen alot of clogged air filters (the service interval is way too long in my opinion) which will cause additonal smoke.

A bad CDI injector will smoke alot but you'll notice the engine will be very rough at idle.

Smoke is normal at full load and when cold/long idle periods, smoke when cruising especially in a turbo isn't. You'll have to judge it for yourself. I've heard very good things about both engines though, so you can't go too wrong.