What type of oil is recommended in a Mazda b2500 diesel turbo inter cooler engine?

Mazda recommends their own (naturally) diesel oil sold (for a ridiculous price) at dealers and can void your warranty if it isn't used!





I use Rotella T (Made by Shell Oil and sold in quarts and gallons at Walmart and in gallons at any truck stop), although Delo (Mobil Oil) is a good substitute. They are designed for turbo diesels and although they don't have the 5-30 designation called for in the book, (they are 10-40) they are very good oils. These are the 2 used in most large and medium diesels, and work well in the small ones too. (Do not use them in anything but a diesel engine as the additives aren't designed for gasoline engines.)





The real secret is to use 1 brand only. Each brand uses different additives to give the same results and mixing brands also mixes additives that may counteract each other. Using good diesel oil and doing changes (including filter) at the recommended intervals is what makes a diesel last forever. To really extend a diesel's life (and to find every leak in the engine) Every 3 or 4 oil changes substitute a quart of Lucas, or Howes Diesel Oil Treatment for one of the quarts of oil. It will clean out the carbon quite well, but remember that carbon is sometimes what is blocking leaks in gaskets.