Originally Posted by colejl' post='504283' date='Dec 8 2007, 11:26 AM

That's the trouble. Because the engine is so refined (for a diesel ) any resonance and harmonics are magnified. It would appear the engine has some natural resonance issues around the 1,700 and/or 2,000 rpm mark and each build will respond differently. The 'good old days' of serious clatter and rattle hid all other issues!

I wonder if an engine remap would help? It's quite possible the factory tuning (for emission reasons sometimes) is affecting matters?

Originally Posted by narvselius' post='504296' date='Dec 8 2007, 12:03 PM

Actually, the noise level from the 2.5 lit diesel has also been mentioned by the German Magazine auto, motor und sport. When testing the 325d (first car with the new engine) they complained that around 2000 rpm there was an "unpleasant noise" and they concluded that the engine wasn't one of BMW's best. What's interesting is that the 3.0d hasn't this noise at all, baring in mind that the main part of the engine i the same. But apparantly there are so many changes that the two engines are more different than I first thought...?

Originally Posted by 525d MSport' post='504297' date='Dec 8 2007, 10:21 AM

You are absolutely right with your statement.

I have thought about a remap - would be interesting to kill two birds...more power and noise gone!

Regards,