1999 Chevy Blazer. Overflow bottle keeps going dry. Almost 2 gallons of anti-freeze have disappeared within the last month. Pressure test has been done. Sometimes gurgle sounds from under dash board. Where can the coolant be going?
The usual suspect in a GM of this vintage with a V6 or V8 is the intake manifold gaskets.
“Sometimes gurgle sounds from under dash board.” That is because the coolant has been low and there is air in the system.
Have a compression test done, sounds like a head gasket. Just about anything else should be easy to find by seeing where the leak is.
Without a doubt it’s the intake manifold gaskets. Very well known problem.