After 2000 miles of driving, I found the oil was at the lower end of the check stick. Added what I thought to be 15W-50 synthetic but it was actually 5W-30. Will this be any problem? I think 5W-30 is too thin for this big V8. Should I go ahead drain all the oil out and fill it up with 15W-50 or I could drive it for a month or two?