I noticed it on Sakhal when i found one of these vehicles: Olga, Ada, Gunter, Dirtbike, boats.

When you get in, you can see that the tank and the radiator are completly empty. Common denominator in the cases above seems to be that they all allready have been used, because i found them in the woods or crashed on the road. Only once i found a boat with half a tank, i'm guessing it just spawned.

The only thing i can think of which causes this issue is, tanks get emptied when people are being too far away from the vehicle or after the restart.

I tested it with a boat with a half full gas tank. I went to a remote island where i parked the boat hidden away between ice sheets (tank was still half full). Came back the next day (roughly 20 hours later). The boat was at the exact same place where i left it, but the fuel tank was on red.

Same with the gunter. Filled the gas tank to a quarter and the radiator fully, then i stashed it in the woods. Came back later to use it and everything was empty. This also happened with the dirt bike.

TO REPRODUCE: Maybe try getting away a certain distance from the vehicle then coming back or checking back after the restart.

UPDATE:

• I took one car to the miltary island and looted there. When i was away from the car there was a server restart. When i came back, the fuel tank/radiator were still full. So server restarts are not responsible.

• I brought the car back and went away from it (ca. 600m). Then logged out and came back after 30 min. Fuel tank /radiator were still full.

• My guess now is, that it has to do with the timeframe between interactions with the car. Maybe if it's long enough, the tanks get drained.

Fuel tanks and radiators not empying themselves.