is it suppose to have coolant/water? or empty? right now my rx7 has no water in it hot or cold. normal?

 

No coolant = bad! It should always be above the "LOW" line on the side.

With the engine cold fill it to the "FULL" line with a 65/35 water/coolant mix. Check the radiator level as well, as it will probably be low if the reservior is empty. It should be completely full.

 

its exactly what you said...an overflow tank....it is suppossed to hold the overflow of the coolant mix when the mottor gets way too hot...that other weird resiviour is for the cold idle cam fluid....As long as the rad has fluid to the top while running,(put a big rag over your hand to check it if already hot.) it's fine.....
kurt