I have an insane idea floating in my head. Using the same brand and weight oil for my 1994 Nissan 4x4 V-6 and my wife's 2000 Trooper. The truck has 96k on it and uses no oil, the Trooper has 56k and uses 1qt per 3k miles. I live in NC so it rarely gets into the teens but does get darn hot in the summer (100 mark or so) and I do some interstate driving with both. People on this board have good things to say about the Castrol oils so I thought the high mileage formula would work well in both vehicles (one is older and one uses some oil ) I plan on using either 10w-30 or 5w-30 weights and chaanging every 3k-3.5k miles. Any input?