Greetings all, I spent about what seemed like 2 hours reading though threads on oil, etc this morning, hoever only got a few of my questions answered. 1st un-answered question....how many quarts of oil does my 81 300SD hold? Secondly, I have a friend that swears by the Mobile 1 that he uses in his 80 300SD, but after reading this morning it sounds like more are liking the AMSOIL. I needed to get this done today so I went with the Mobile this time, however not sure what would have been the best weight to use. I'm in Dallas and it is fixin to get hot, or it will be between now and the next oil change. It was recommended a higher visc. to me by someone, so I got 15W50. Any feedback would be GREAT!

Thanks, Chris