most likely cause is your heater core leaking
Under hood passenger side near fender
the cooling system is a pressurized system with the radiator cap designed to release pressure and expanded coolant into the overflow can. there is a drain however, look at the bottom of the radiator on the passenger side for a wingnut, loosen it and the coolant flows out.
The 1995 Chevrolet Astro and coolant temperature sensor can be found on the front of the engine. The coolant temperature sensor will be a few inches above the thermostat housing.
Where is the coolant temp sensor on the 1998 gmc safari awd
Drain radiator at bottom or rear of radiator
if you have a leaking water pump gasket i thing bay a new one is better
There is a petcock just below the lower radiator hose.
The coolant temp sensor will be located very close to the thermostst housing.
On the passenger side in the black box
Averaging about 16 MPG.
If you have just defrost and a fan setting of high, it is the small diameter vacum hose that runs from the drivers side of the throttle body to the "T" near the passenger fender. athis small hose gets very brittle ..