Diesel Power = Torn Harmonic Balancer

On the left is the original harmonic balancer. On the right is the redesigned one

BMW used to have diesel engines in the USA, until stringent emission laws prevented them from bringing them here anymore. They continued to have them in different parts of the world, and after a lot of work to meet emission regulations, they managed to bring the 6 cylinder diesel engine back to the USA in the E90 and the E70, and let me tell you, they are really powerful. They have so much torque that we've seen a few of the E90s break the harmonic balancer (the big pulley in front of the crankshaft that is used to drive the belt and accessories). When this happens the engine runs but you have no power steering, A/C or alternator to charge the battery. Also, you can smell rubber burning pretty bad. Luckily I've only seen a few of them, and apparently the problem has been corrected by a re designed, beefier harmonic balancer. Now people can enjoy the gobs of low end torque without worrying.....at least about THIS issue. BMW has learned a lot about diesel engines in the USA now and have made drastic improvements on the newer diesels and have now released the 4 cylinder diesels in the USA too. More to come on diesel repairs soon!

You can see on the old style how the rubber is ripped around the center hub. The hub will spin, but not the rest of the balancer.

New balancer has a lot more rubber to prevent reoccurrence of the issue.