Pete, The original question was ref using vegetabl oil.
The subject has caused much debate with the Delica owners club. There are several threads that can be checked out if you visit
Mitsubishi Delica Owners Club UK - Free to join delica l300 and l400 owners community
Essentially the advice I have been given is that for basic diesil engines vegetable oil can be used and it is best to introduce it at a raio of about 10%.Now, the CRDi engine may not fall into the category of 'Basic' but the original 2.9 diesil td probably does.
Some Deli'owners run on much higher concentration of vege' oil.
Be careful though if you do decide to use it, personally I would recommend against it (but I'm a coward). The Inland Revenue insists that any vehicle running on substitue fuels must declare and pay the applicable rate of tax on a per mile basis , in advance!!!!
Should you get pulled over ,dipped and caught out then they have the authority to impound the vehicle and can charge back tax for the full period that you have owned the vehicle, regardless of how long you have actually been using the vegy juice. Quite how they work out your mileage I don't know but I'm not prepared to risk it
Check out the new Shell Diesil that is being introduced, supposed to be more efficient and cleaner, though naturally no cheaper.
Anyway Pete, whatever you decide, good luck and keep us posted.
Cheers
Mark