What problems are there in the design of vw engines?

As early as the late 1970s, Volkswagen began to think about replacing their rear-engined Type 2 vans with a more modern, front-engined, water-cooled design, as they had very successfully done with their passenger cars earlier in that decade. The reason why in 1980 they still introduced the new rear-engined T3/Vanagon instead is unclear; rumour has it that the unions feared the closing of VW's Salzgitter factory, where the boxer engines were built, and thus forced the new design to continue to use a boxer engine, and hence be rear-engined. Truth or not, the fact remains that the front-engined van was delayed until 1990.