I found out that it was still some air in the system after the water pump was replaced. I heard that on some cars it could take a couple of hours just to burp all the air out after a water pump has been replaced, so i have released more air out of the system by running my car with the radiator cap off until it warmed up and some of the antifreeze boiled out. that let me know that air was being released. i topped it off and haven't had the problem again :D Thanx for the reply though. I may need that info in the future.