2006 lacrosse water noise

Our lacrosse has 121000 miles on it, no real problems, but I can hear water sloshing around. It sounds like it is in the heater core. I am worried the water might freeze and brake something, has anyone had this problem?

Check your coolant level, its low. Then find the leak.

I did add some coolant when I changed the oil. This sound has been going on since last summer. I haven't noticed the temp rising. I will keep closer tabs on the coolant,and for leaks, hopefully it not a manifold problem. I think I have had a manifold leak on every car we have owned.

The noise is pretty typical of a low coolant condition, air being pushed through the heater core. Bleed out the system and fill and the noise will go away. Like you said, keep and eye on the level and look for leaks.

Where do I bleed the air off.

I like to use the kind of funnel that you attatch to the radiator, or surge tank. Fill the funnel and start the car. Let warm up, rev it up a little and let off. keep and eye on the coolant in the funnel for air burping up and out. If cars temp starts to get too hot, shut it off for 15-20min and repeat till no more air is seen.