Location: Just North of Detroit, a surprizingly great city
You need to refill with a 50/50 mix of antifreeze formulated with SCAs (supplemental cooling additives) designed for diesel engines otherwise your engine will self-destruct from the inside out. The additives prevent, among other things) pitting from occurring on the outside of the cylinder sleeves. DO NOT use plain water of any kind unless mixed with the appropriate antifreeze with SCAs, and then use only de-ionized or distilled water to minimize solids present in ordinary water sources.
Jon and Alie Kabbe
Started with 77 Coach
Now have 39' 93 coach
2007 civic toad
While you can use most heavy-duty coolants, it must meet specs.
Water quality requirements:
Calcium/Magnesium Max. 170ppm as CaCO3+MgCO3
Chloride Max. 40ppm as CL
Sulfur Max. 100ppm as SO4
Use of tap water is ok as long as it meets the above requirements or you can use distilled water. Pre-formulated antifreeze, such as Fleetguard Compleat provides high quality water and the correct chemical balance.
If, as your username implies, you have a 2 stroke Detroit Diesel you should consider using Detroit Diesel's coolant....Super Cool. It is formulated for their engines. I use it cut 50/50 with distilled water. Costs about $20/gallon uncut, so end cost is around $11 cut 50/50 with distilled water, which is quite cheap.