or install an external oil pump that you can run before starting up.
Hook it up thru the external oil cooler lines.

Most Merc diesel engines do lasts a long long time, unless you do these external oil pump right from the start. Otherwise all the damage had been already done.

For Merc diesels is a bit harder to crank the engine a few secs prior to firing up.
Gas engines/ VW diesels can do that if you don't send any power to the ignition coil or power to the fuel solenoid on a VW.

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