It would help to know what engine you had... if it's not a glider, the 2006 Volvos in North America were available with the Volvo D12 or D16 engine, the Cummins ISX or ISM engine, or the Caterpillar C11, C12, C13, C15, or C16 engine. Also, are the hoses blowing off of their connections, or are they just blowing out?
There are two hoses for the 2006 Silverado heater core. Loosen the clamps where the hoses go into the firewall. Twist the hoses gently to break them loose. Slide the hoses off. Follow the hoses to the other end, and repeat the process.
Fuse, switch, speed resistor or motor.
If your van has rear heating it will have hoses and a heater core back there, that is most likely the source of the leak.
The 2006 Volvo S60 has 20 valves.
The 2006 Volvo XC70 has 20 valves.
The 2006 Volvo C70 has 20 valves.
The 2006 Volvo S80 has 20 valves.
The 2006 Volvo XC90 has 20 valves.
The 2006 Volvo XC90 is a gas-powered vehicle.
The 2006 Volvo C70 has an inline 5 engine.
The 2006 Volvo S80 has a 5-speed automatic.
The 2006 Volvo S60 is a gas-powered vehicle.