[ngoma]

More important than "ran when parked" is "started well when parked," meaning: Was it always easy to start, at the time it was parked?

If so, you will likely have an easy time of it, as nothing much will have changed over the 3 years. Diesel fuel does not go bad as quickly or easily as gasoline. Of course, rodents could have chewed thru the wires.

In my experience, the hardest one I had to start, after an unknown number of years, required a quarter teaspoon of motor oil poured into each cylinder. Then it roared to life immediately. For some reason the rings were not sealing enough to build sufficient compression.

You will need a good strong battery, good jumper cables, battery charger.

The most unpleasant part for me is cleaning all the glass (inside & out) and the mildew in the interior before even wanting to drive it any distance. Don't ruin your windshield with shaggy windshield wipers.