I have a '98 Mercury Tracer Wagon with a 2.0L. About a week ago the cooling indicator light came on so when it was cool I added some water. A day later the engine started making a noise (not real loud) I did a quick check of gauges and lights no trouble then the engine stopped. I was close to church so I got a ride and went on. After church I went back and discovered the radiator cap was off. There was antifreeze all over the engine. I turned it over and it started. We pulled it home. The following after noon I started to check it out. It was hard to start But I was able to do so. It sounded different so I cut it off. I checked for OBDII codes and there weren't any. I started it again and the engine didn't sound right assuming it had over heated and I didn't notice I decided to put in some oil treatment to quiet it. I let the oil treatment get hot so it would flow quicker, added it and started it. I went back to listen (maybe a minute passed) I removed the radiator cap to check the level and was sprayed. It wasn't hot. The radiator lines were hard like they were under full pressure. I noticed the fluid in the reservoir was rolling. I killed the engine and checked there was no pressure in the radiator. The hose was squishy. Any one have a idea what might be going on?

 

Some vehicles become air bound when the coolant level gets low enough.
There are several ways to correct this, one is to use a vacuum pump to pull the air up and out. Another is to loosen some hoses to allow the trapped air to rise and exit. Patience will usually help when allowing the air to rise and exit.

 

Just pull them loose from the radiator?

 

You may need to open some of the hoses on or near the top of the engine itself.

 

I assume loosen/open them and add water to force the air out. Would this air cause it to run rough or is this more likely a result of the engine components getting wet? and if is is just the wet issue is there a way to discover which components this entails or will it be trial and error?

 

You have the right general idea, and that is to get the coolant in and the air out. However you do it as long as it works.
It is a good possibility that coolant got into a few places it shouldn't be. Sometimes it will dry on engine getting hot enough otherwise you may need to wash it off with water and then allow it to dry.
Hopefully the engine didn't get too hot or it could have done some damage.
If after cleaning and allowing it to dry the engine still runs rough there could be other issues.

 

OK, will give this a whirl and post the results.