How long should one run a motor safely without a water pump belt?

If the original oil filter has not been thrown out, it should be dissected to look for bearing material. If gone, the current oil filter should be dissected.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked