Severe coolant leak - please help

I am trying to help my computer challenged father in law with his 2000 Intrigue. I love this forum, I use it regularly for all of my vehicles. The father in law can't figure these out. Anyhow, he has a 2000 Intrigue that developed a sudden and massive coolant leak. He shut it off one night and woke up the next day to find coolant all over the garage floor. I would suspect a head gasket, but there is absolutely no coolant in the oil. If it was a head gasket, wouldn't there be coolant in the engine oil? My next guess would be the intake manifold. It's difficult to find the source of the leak as there is coolant everywhere now. This engine never ran hot or overheated in the last few weeks, or at all for that matter. Any past experiences?

It may seem like a stupid reply, but our vehicles had mice climbing into the engine and nesting in the air filter cabin. I can only think that they felt the warmth from the engine. You never know what they could have chewed or knocked loose. Let us know.

goto autozone to rent a pressurized cooling system tester...

that way, you can fill it up w/ distilled water, pump it up to what the rad cap's rating while engine is cold, & see the pressure on that gauge drop/ will evidently see where it's leaking:

i.e. water pump seep hole, intake manifold gaskets, a hole on the heater hose, radiator endtank/core leak, etc.

see autozone's website for the free loaner tool link pic... other parts slingers may also have these for free to use...