my friend has a 2007 buick lacrosse with the 3.8 v6. anyway he likes to monitor his coolant system with all the dexcool nonsense. so since he started monitoring his cold level in the reserve tank,every week or so before inital start up after sitting all night. He just had to add 3.5 ounces of dexcool to bring it up to the cold fill line. So would this be considered normal coolant loss in a 5 1/2 month period with 5500 miles placed on the car during that time?