My BMW 5 Series' DPF fault also caused the turbocharger to fail - is this to be expected?

I own a 2007 5 Series BMW diesel automatic. The car has a full service history, but is high mileage at 85,000. The DPF light came on and the message said that the car was safe to continue driving, however I may experience loss of power. I spoke to my local garage and did an internet search. The DPF light still came on saying safe to drive whilst I was looking into the options and then the power started to drop off.

There was no option but to replace the DPF, which is an expensive part. Despite a new DPF the car still lacked power and further investigation identified that the turbo had failed. The garage believes that the blocked DPF caused a back-pressure into the turbo causing it to seize. If this is possible then I am extremely disappointed that the warning light kept saying safe to drive when it blatantly wasn't (the gap between the light and the turbo failing was only just over a week). It transpires from my discussions including BMW that the DPF will need replacing anytime between 80,000 and 120,000 miles regardless of how it's driven and what fuel is used. I would be interested in your thoughts with regards to the DPF failure affecting the turbo.

Asked on 5 May 2012 by AP, West Molesey

Answered by Honest John
This is why I am warning readers against buying diesels around a dozen times a day. Yes, DPFs do generally only last between about 60,000 miles and 120,000 miles and cost anything from £1000 to £2000 to replace. It's an additional cost legislated into diesel cars by the EC to qualify for EU5, and all diesels need a DPF to meet EU5. Add turbo failures from the back-pressure problem or coking up of the oilway to the bearing, EGR problems, Dual Mass Flywheel failures on manuals and DSGs and a diesel owner could wind up forking out £6000 on repairs and replacements between years three and six.

In the USA, the NHTSA requires DPFs to be warranted by the manufacturer for eight years. There's no such requirement in Europe where the EC is basically in the hands of the big car and car component manufacturers.
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