I just drained the oil of my jeep with a 283 in it. I acquired it from my sisiter recently and it has been sitting for many many years. When I opened the drin plug water came out first and then the nasty oil. I also took off the filter..man it was nasty. My question is besides putting new oil in, should I do anything else? does that mean a cracked block? or could it just be cndensation? I am adding 4 quarts of oil only..in anticipation of an oil additive? should I add one? thanks..Paul