Losing coolant in 2001 jeep grand cherokee. No sign of leak under hood. Nothing on the ground.

Had dye put in it and nothing is showing up. Please help with any suggestions.

Head gasket. Your coolant is coming out the exhaust in the form of white smoke.

could be going into your oil from water passage to oil passage, then boiling off and going through your pcv valve into your intake. there are several different ways to blow a head gasket. get a competent mechanic to pressure test the coolant system. the guy you took it to should of been smart enough to do that.

I'm not much of a believer in magic. It has to be getting out of the system some way. I would start it up on dry pavement and let it idle until the thermostat has been open enough time for any escaping liquid to make it to the ground possibly 10-15 minutes after it opens. Watch the exhaust for steam. Then shut it down and go over the radiator, cap, hoses, reservoir, and the water pump. Don't forget the heater inside and it's hoses. If that produces nothing, look at the oil and the air filter for any signs of liquid.

If, after all that, there's no sign of coolant escaping anywhere, I may change my belief about magic. :-)