I own a diesel toyota fortuner in the philippines.

hi there kababayan, The type of oil used plays an important part in engine maintenance, but unfortunately, diesel engines require frequent oil changes due to the type of combustion process it uses. It won't matter if you use synthetics or ordinary diesel oil. if you run your suv at high rpm most of the time or you happen to be a jack rabbit type of driver then you must perform frequent oil changes. Have you noticed that when you put new oil in its color is clear yellow or clear red(or any color depending on the type/manufacturer) and after you have used it for a week or so you check the dipstick it turns black. Well the black part is carbon w/c is a result of combustion seepage around the pistons and valves w/c has a normal percentage for different engines. This fine carbon that is mixed with the oil goes around the engine's moving parts w/c eventually serves like a fine sand paper scratching the moving parts so very slightly. The oil filter cannot filter this fine carbon. If you don't change that often, the oil becomes sludgy then overheating comes in and eventually engine breakdown. So, if you use your suv most of the time or you take it for long drives, it is better to change your oil frequently. If you'll ask me how frequent, well if you have the budget, 3 month at the most, if you use it everyday.

Hope this helps.

any 15w/40 diesel oil is as good as another in todays world,toyota oil is one of the major companies oil anyway,if you stick to caltex esso shell ,bp any of the major oil producers you cant go wrong ,,even pensoil valvolene no worries