On the "if there is already antifreeze in the engine" statement, I meant versus having straight water in the engine. You have air suspension, don't go under the bus and drain the airtanks and get crushed. Wait until it warms up and have the air tank drains plumbed to the wheel wells if you think its an issue. Stay warm, don't wake up the bus right now, its to damn cold and you are not going anywhere anyway.