Check the oil for water and check the water for oil. Check the oil level when the car had been off for five minutes or more and is on a level surface.

The oil will be milky brown if it has coolant/water in it.

Also make sure engine has oil. These little eco turbos rely on really clean and often changed oil to stay together.

Next up, fill the radiator up with liquid, leave radiator cap off and start the engine.

If you see air bubbles coming up in the radiator cap neck that means a head gasket has a leak and needs to be replaced. Not easy or fun but doable.

If you see oil in the water or water in the oil that’s probably more expensive than you want to deal with.

After you’ve done the air bubbles coming up from radiator neck check put the cap back on and see where its steaming/leaking from.

I don’t know sonic radiators but this type of car has a plastic and aluminum radiator that can easily develop cracks in the plastic top and bottom. If it has a leak that is not on the seam where the aluminum and plastic meet you can JB Weld it as a temporary fix until you can afford a replacement radiator.

Check for fresh liquid drips after you’ve been running the car in place for a while. (good to do after the radiator white smoke check).