Hi. I have a P01FO code on my SUV. I wonder if there should be any coolant in the recovery/surge tank when the engine is cold? If yes, how much? Currently, when cold, the tank is empty. 

I added some coolant to the recovery/surge tank and let the engine run for around 20 minutes; next, I drove the vehicle for about 20 minutes. When I returned, the surge tank was filled to the hot level. Hours later, I checked with a cold engine; the surge tank was empty.

I do not have any signs of the coolant leaking onto the floor, and the motor oil is not milky or shows any other indication of coolant in it.

Another thing is I do not have any of the characteristics that go along with the code P01F0 outside of the check engine light. The temperature gauge shows the same temperature level. The needle is on the line right before the halfway point between 'C' and 'H". No reduced power steering assist warning. The heater pumps out heat. The AC is cold, No hard starts, No change to the exhaust fumes. 

So, I am wondering if the cooling system is low on coolant since there is none in the recovery/surge tank when the engine is cold, and if that is the case, how much should there be?

Since I live in Michigan and have an unheated garage, I would like to avoid replacing the coolant temperature sensor or the thermostat until warm weather returns.

Thanks

Mark