- Fuel Pump needs fuel to cool to avoid damage. Below 1/8, it is risky. Not to mention being stranded.

- When siphon pump fails (quite a few in E35 5-series forums), fuel is not pumped from L to R side, where the fuel pump is located. When that happens, the fuel pump fails due to overheat.

Look into E39 5-series forum, you will see quite a few like this.

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1998 E39 528i 5sp MT
2006 E53 X5 3.0 6sp MT