30-32 degrees tonight, is there anything I can do to stop my radiator/engine from freezing?

Not really, this is why they made antifreeze, you can let the engine idle or put the car inside with a heater. Not too many things I can think of on that. Here is how to drain and fill the system which can prevent it from freezing. Please check out the images below to see how on your car.

https://www.2carpros.com/articles/coolant-flush-and-refill-all-cars

Make sure the engine is cool before you start, the cooling system drain plug is on the radiator left side lower tank.

Fluid Types

ENGINE COOLANT

The cooling system in your vehicle is filled with DEX-COOL engine coolant. This coolant is designed to remain in your vehicle for 5 years or 150,000 miles (240 000 km), whichever occurs first, if you add only DEX-COOL extended life coolant.

A 50/50 mixture of clean, drinkable water and DEX-COOL coolant will:

Give freezing protection down to -34°F (-37°C).

Give boiling protection up to 265°F (129°C).

Protect against rust and corrosion.

Help keep the proper engine temperature.

Let the warning lights and gauges work as they should.

NOTICE: Using coolant other than DEX-COOL may cause premature engine, heater core or radiator corrosion. In addition, the engine coolant may require changing sooner, at 30,000 miles (50 000 km) or 24 months, whichever occurs first. Any repairs would not be covered by your warranty. Always use DEX-COOL (silicate-free) coolant in your vehicle.

WHAT TO USE

Use a mixture of one-half clean, drinkable water and one-half DEX-COOL coolant which won't damage aluminum parts. If you use this coolant mixture, you don't need to add anything else.

CAUTION: Adding only plain water to your cooling system can be dangerous. Plain water, or some other liquid such as alcohol, can boil before the proper coolant mixture will. Your vehicle's coolant warning system is set for the proper coolant mixture. With plain water or the wrong mixture, your engine could get too hot, but you would not get the overheat warning. Your engine could catch fire and you or others could be burned. Use a 50/50 mixture of clean, drinkable water and DEX-COOL coolant.

NOTICE: If you use an improper coolant mixture, your engine could overheat and be badly damaged. The repair cost would not be covered by your warranty. Too much water in the mixture can freeze and crack the engine, radiator, heater core and other parts.

If you have to add coolant more than four times a year, check your cooling system.

NOTICE: If you use the proper coolant, you do not have to add extra inhibitors or additives which claim to improve the system. These can be harmful.
Capacities

Cooling System Including Reservoir .................... 12.2 quarts (11.6 liters)

NOTE: All capacities are approximate. When adding, be sure to fill to the approximate level. Recheck fluid level after filling.

Check out the images (below). Please let us know what happens.