While "free oil refill course" might be a misunderstanding, there are many free online courses available related to oil and gas, car maintenance, and related topics. These courses can cover various aspects, from safety and industry standards to practical skills like changing oil. While "free oil refill course" might be a misunderstanding, there are many free online courses available related to oil and gas, car maintenance, and related topics. These courses can cover various aspects, from safety and industry standards to practical skills like changing oil. While "free oil refill course" might be a misunderstanding, there are many free online courses available related to oil and gas, car maintenance, and related topics. These courses can cover various aspects, from safety and industry standards to practical skills like changing oil.