my 06 impala does not take fluid from the reservoir tank,

overheats for the 1st time yeasterday, but it was missing about a quart of coolant, but the serservoir tank fluid was intact....that how I realized it was not pulling fluid from there

Pressure test the cooling system . Could be as simple as replacing the radiator cap

I shouldn't overheat with only 1 quart missing from the reservoir tank. I suspect it either has air in the cooling system or there are other more serious issues such as a head gasket problem.

I also had a crossover tube small leak, I'm guessing it was taking air from there and wouldn't create the vacum effect in order to pull fluid from the resevoir tank....I replaced those gaskets saturday...now I will test these for week....I also beleive the radiator cap is blocking the flow....the one I bought does not look very reliable (the inside is superhard and the thread put a little resintance from middle to end)........Thanks for all suggestions, it is allaways helpfull...I'll get back to you with results this comming saturday

I replaced the cross over gaskets and it worked, meaning it pulled coolant from radiator reservoir tank, then a week after started leaking from the head gasket in the back and the water pump gasket as well......it is no much leaking , just about a 12 ML in two weeks, I have to decide if I would take all that apart...I learn that as far as there is a leak some where it would stop to sucking coolant from reservoir tank