That seems like a long crank time, you sure the battery is not low. When my solenoid failed it would not make any click sound at all. If it does it again you can make sure it is not the solenoid by whacking it with something hard, then trying to start again.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine