Losing coolant but do not know where.

[Signature620]

Is there much coming from your overflow hose? Try putting the hose in a bottle for a day. Is it blowing white smoke? Check for signs of coolant when you drain your air tanks. Check the condition of your radiator cap. Check for coolant in your Egr valve or outlet of Egr cooler. That's enough checks to keep you busy for a little while, hahah.