2003 Vw passat 2.8l dumping coolant from tank

[Dev622]

Hello guys and gals. I need ur advice/help. I purchase an 03 passat v6 today. After it warms up it will push the coolant out of the reservoir. Note, it's not overheating. The guy I bought it from said the coolant reservoir exploded on thursday. He said his local mechanic said it needs head gasket. What's ur take on it? When I remove the over flow hose from the reservoir and increase the rpm, very little coolant comes out. After I let go of the pedal, the coolant gushes out on the over flow hose. Thermostat is opening. Guy said the water pump, thermostat and belts were replaced last year. The problem started Thursday when the old reservoir exploded. Pls let me know what you think. I was thing of replacing the belts , water pump and thermostat with oem.

[IoE GLX]

so its not coming out when you hit the throttle but when you let go it does?

[Dev622]

so its not coming out when you hit the throttle but when you let go it does?

Yes. I'm thinking the head might have crack causing compress air to get in the cooling system.im going to put shop air in each cyl and hear for bubbles in the cooling system

[IoE GLX]

.... ****, im stumped.. was anything replaced on the car like any valves?

[IoE GLX]

sounds like a circulation problem as far as flow goes, a head crack could explain it, maybe throttle opens it up and letting it go closes it up but still flowing so it spills.. ehh idk dont take my word for it just trying to troubleshoot

[Dev622]

Update. I put 40psi shop air to each cyl. No air bubbles in cooling system. Maybe I need to put more? I was thinking to do it again with 120psi. Any suggestion?