[Dave W]

There is a service bulletin out on it and the dealership has purged the air 4 times already and it goes away slightly for awhile and then comes right back strong again

 

[alanlans007]

I would say you have a hose that is slightly loose. On cool down the cooling system sucks air back into system causing an air pocket. Have fun, these suck, welcome to my world.

 

[Mr. Jon]

My 99 Buick Century has always done the same thing since 1999. I just always thought it was normal, since I have had no Problems with it.

 

[good_fatrabbit]

check you AC drain tube for blockage.