The worst favourite for the time for changing oil is that one:
http://www.imcdb.org/vehicle_245944-Volkswagen-Pick-up-Typ-2-T3-1990.html

Shit! You cannot reach the engine from the top as at the Bus- or Transporter-version. You have to pull out a two-part funnel with a very small diameter. Only for filling up the oil, you need over half an hour. Due the narrow diameter you cannot only fill it drop-wise. I ws so fucked up with it, when I had to do this work at my military-service.