Make this simple. Slow speed bottom out 5 mph. Drive 2 miles and park, huge coolant puddle (about 1/2 gallon) behind front passenger tire. 2 miles to parts store fill with coolant. Chevy dealer says pressure check shows no leak. Smells of coolant still, stays under 220 ac or not. Any suggestions or reasons? Was this a freak accident on a really hot day(100)?