volvo 850 tdi startproblems

Hello dear Volvo community, first of all thank you for your many contributions in this forum that have already helped me with a few problems. However, my Swedes tank has a little problem for a few weeks, to which I have not found a solution in the forum so far. Vehicle data: Volvo 850 TDI First registration: 11/1996 Kilometer level: approx. 265,000 (about 38,000 of me) Automatic gearbox Sometimes when I switch off the car after a ride (short or long does not matter) and want to start again a few minutes later it doesn’t start. Fans, air conditioning, radio work when I turn the ignition key, only the engine doesn’t make a sound. Only when I open the hood and wait for good 10minutes it jumps on as if nothing had ever been done. Does any part of it take no heat, or is the starter vllt. over? I changed the contact plate from the ignition lock months ago after the great instructions from burfil. Thanks already for your answers!