This week I'm going to remove the cab heater coil since it is leaking and I want to try to repair it. The unit maintenance manual says that the cooling system needs to be drained for this. I'm tempted to leave the heater valve closed and take my chances, but my real chances are that I'll disconnect the heater hoses and I'll have to fight with keeping seven gallons of coolant off the cab floor!
With that being said, I asked my local Cat dealer what type of coolant the 3116 is supposed to use. The dealer's parts guy said the preferred coolant needs to meet Cat EC-1 spec. Acceptable coolants need to meet ASTM D4985 or D6210 spec. I attached coolant info from the Cat dealer to this post (should also be helpful to those who have the FMTV).
I've never flushed coolant before, especially on a big truck. Is it a matter of feeding water from the garden hose through the surge tank, or is it something I'm best not doing at this point? I haven't noticed any temperature issues running the truck, even after topping it off with two gallons of NOAT stuff I got from Tractor Supply.