I picked up 4 gallons of Delo 400 XLE 10w30 diesel oil a few months ago, with plans on using it in a vehicle that has now been sold. What are the chances it could be used (effectively) in a '91 Mazda B2600I 2.6L fuel injected 4 cyl? If not the Mazda, maybe a '94 4.0l Jeep 6 cylinder?