Having said that about Lucas pumps and recognising their unsuitability for running on viscous fuel, there are some on the veg oil forum who have run them on v high % veg mixes for many tens of thousands of miles, making sure they 'twin tank' their car - ie have a separate fuel tank for starting and stopping on diesel, to help prevent pump failure. The addition of a plate heat exchanger for winter use would make sense in this situation. Equally people have come to grief running Bosch-pumped cars on veg oil without checking injectors or glow plugs (poor injector spray pattern means incomplete combustion and eventual ring-gumming/sump oil polymerisation - which means you need a new engine not just a new fuel pump), or using waste oil which hasn't been thoroughly dried - which will damage the pump and injectors, but will steam clean the combustion chambers.
I've read on the French forums of plenty running EPICS single tanked on a 80/20 veg/diesel in summer, 50/50 through winter with no problems over several years. The big no-no is revving them much before there's some heat in the engine, obviously!
Don't forget to change the engine oil more often as a precaution against lube oil contamination, every 3k in winter. Looping the fuel supply makes sense in winter especially with shorter journeys.
PeterN: "Honest John's forum put the last nail in the coffin of owning a 2000- car. Many were still servicable, but CR, DMFs and needing fault codes read because your horn doesn't work - no thanks. All my life I have generally understood cars - until now."
