maybe not. check engine oil for color and quantity. if oil is white to grey, then there is coolant leaking into engine.no pressure might be caused by bad radiator cap.this will also allow coolant to escape
Where is it leaking? That pressure test sounds funny, why would you pressurize only the pump and radiator? If you are leaking coolant outside the engine, locate the source. If you are losing it from the radiator but cannot find a puddle suspect a head gasket problem. Check the Radiator cap first, if it is bad high pressure coolant will travel back to the overflow bottle.
I would check the hoses leading into your radiator, and also the overflow for antifreeze. If that is not the problem, it could be your heater core. Your heater core might be leaking, you might have a hose leaking
Check the water pump. Examine it for traces of dried coolant that might be leaking out of the casting.
I'm assuming your grand am has a 3400 v6 which are known for intake and head gaskets leaking. so its possible that one of those gaskets are leaking so bad that coolant is leaking from intake/heads down onto your valvetrain and then down into your oil pan. more than likely its your intake gaskets leaking.
It means if it is losing coolant and you don't see a leak on the outside, it is leaking internally. This could be serious. Have a trusted mechanic check it out soon.
The overflow tank is either cracked or its overheating and leaking from the cap
You may have a bad radiator cap.
Could be thermostat not opening causing a back pressure
It could be the coolant overflow tank that is leaking.
it is a big possibility it is leaking from your water pump. i have a 2001 intrigue 3.5l twin cam v6 leaking from the waterpump, and am currently replacing it as i type this.
Bad head gasket? Bad thermostat? Defective radiator cap?
To determine if your tub is leaking from the overflow drain, fill the tub with water and observe if the water level rises above the overflow drain. If water is leaking from the overflow drain while the tub is filled, then it is likely that the tub is leaking from the overflow drain.
Run a pressure test on it.
do a coolant pressure test.
Is it too full? Well some vehicles are equiped with a little hose that will let coolant out if there is too much or too much pressure, but not all vehicles will have it. (If you are talking about the overflow tank, if the radiator cap is leaking, check to see if the cap is in good condition)
Your boiler may be leaking water from the overflow pipe due to high pressure in the system, a faulty pressure relief valve, or a problem with the expansion tank. It is important to have a professional inspect and repair the issue to prevent further damage to your boiler.
Only if the coolant is leaking from the heater core, but you will see this.