Preferred Method

WARNING: This page is about a different car, the 2022 RAM ProMaster 3500, 2022 RAM ProMaster 2500, and 2022 RAM ProMaster 1500. However, it is still accessible from the selected car via links, so may be relevant.

WARNING:

Do not remove the cooling system pressure cap or any hose with the system hot and under pressure because serious burns from coolant can occur.

Remove pressure cap when engine is cold. Remove small amount of coolant. Idle engine until thermostat opens. You should observe coolant flow while looking down the filler neck. Once flow is detected install the pressure cap. Replace removed coolant into coolant recovery container.