Motoring Which? for July contained an informative article about lubricating oil (apart from a very pleasing piece about going through the customs at Southampton, Gatwick and Birmingham Airport by Clement Freud). The effectiveness of modern multigrade oils was firmly stressed and the general advice imparted by these unbiased tests, if we have read the article correctly, is not to buy Jet 30 (which is a straight mineral oil), at all events over any sort of mileage and if you value your engine, and that there are better multigrade oils than the Co-op's Cascade 20W/30. . . . About the "best buy," although the Consumers' Association did not use this term on this occasion, would appear to be Gamages 10W/30 Multi-grade at 1s. 8 1/2d. a pint, compared to 3s. 2 1/2d. a pint for B.P. Super V, especially for those prepared to buy their oil in gallon tins and do the topping-up and oil-changing themselves (thereby effecting a further saving).
But our favourite Castrol is doing very well. For according to Motoring Which? the six leading petrol companies supply about two-thirds of all the lubricating oil sold in this country, almost all the rest being sold by Castrol or Duckhams.