Thank-you Brett; This will be my first time changing my own coolant as I have always had Peterson do it. I printed your cooling system 101 that you posted on 9/26/13 in response to Dennis, and I was impressed by you saying that we would probably get a better job by doing it our selves. I have always changed my own antifreeze on all my vehicles through the years but this motor-home is my first diesel. I do plan on using the ELC coolant. The Caterpillar manual says to use ELC Extender with Caterpillar ELC which seems confusing to me but I will verify with the Peterson Parts Dept.