I did a search and found nothing on my question. I went and bought engine ice for my new shee and the guy at the counter said that I HAD to drain all the old fluid out other wise it will f**k s**t up if it mixes. I asked him how it will f**k s**t up and what would happen if the 2 different fluids did mix, He looked at me like I was just asked the most retarded question in the world. If I do have to drain the old fluid and must make sure it's all out how to I flush the entire system before I put Engine Ice in. Thanks in advance.