Why did my wife's 2010 BMW 118d catch fire?

My wife's 2010 BMW 118d Coupe automatic caught fire under the bonnet last week and completely burned out. Fortunately, she evacuated in time and called the Fire Brigade, but the car is a write off. It was probably due to an electrical fault of some sort as she called BMW Assist out the previous day because the battery was flat and the electrics seemed to have shut down completely. The car is still in warranty by three months and BMW has it for investigation. Have there been other instances of spontaneous combustion amongst 1-Series cars? We have not been in this situation before and don't know whether it is better to pursue a warranty claim with BMW or through her motor insurance.

Asked on 2 February 2013 by NE, Esher, Surrey

Answered by Honest John
No previous reports. Efficient Dynamics is a problem in BMWs driven short distances from cold starts because the battery does not charge and the DPF can clog. My 320dED has been well behaved. However, I abused it last week with four relatively short runs from sub zero temperatures to and from the airport. Near the end of the last run (about seven miles) I smelled burning but it was, of course, the DPF regenerating. It could be that something similar happened to your wife's, but that somehow some paper or other inflammable material got in under the bonnet and was set alight by the hot DPF.
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