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Q: DPF (Diesel Particulate Filter) melted

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Hello. The DPF itself (metal) has melted and caused the DPF to block my BMW 118d. I have bought a new DPF but before fitting it in I need to find the cause for the old one melting as I don't want the same to happen to the new one. Would you know why the DPF itself melted?

My car has 92000 miles.
My car has a manual transmission.

A: Hello. The DPF functions by trapping certai...

Hello. The DPF functions by trapping certain diesel particulates, and periodically goes through a regenerative cycle to burn those particulates (i.e. when you’re on the motorway and get the temperature high enough to regenerate). This is a bit speculative, but perhaps the regenerative phase was not initiated often enough to keep the particulates burned off and too much particulate material accumulated. A regeneration could have occurred that was excessive, creating enough heat to cause the melting you describe. This might occur if you have a high percentage of low-speed or stop and go driving, with few motorway driving segments. I would make sure I was getting regular higher-speed segments of 10 miles/15 kilometers or more on a weekly basis to prevent this accumulation. If you need to have this scoped out by a professional, have a qualified technician inspect the system thoroughly and advise you on the best actions to take at this point.

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