Your uncle doesnt give mutch away!The air filter is in the big metal frying pan with a lid on,on top of the engine it is made of paper,Halfords will probably have one,the oil filter needs replaced + an oil change,go to a fast fit garage and pay up,and the fuel filter,you can buy them off the shelf but if you dont know how to fit it you have no chance.Do your own air filter leave the rest to a garage.The black smoke is a BAD SIGN,replace those filters PRONTO!You may save your van.Diesels run forever but only if the filters are changed at the right milage.
Rich
December 2007