not a mopar question, 09 chev uplander

Lots of great ideas here. But if you use compressed air regulate it down to about 15 psi. Best is to reverse flush it with a garden hose. But it really sounds like low coolant level or air. rev it up to 1500-2000 and watch the bottle does it go down? If so you're low. But it really sounds like air in the system. If possible, remove the outlet hose and burb it. If the heater core is higher than the radiator it can be difficult.