Coolant leak after engine is shut off. on 2007 Mini Cooper

After shutting off the engine taking a drive from office to home 15-20 miles, Coolant starts leaking continuously at 2 spots down the bumper. Got diagnosed for two times from two different persons wasting time and money. Performed thermostat test and done pressure test on reservoir, radiator as well the hoses & got result of good holding pressure in all three components. couldn't diagnose the exact reason for leak and still worrying of the coolant level running out from the reservoir and got frustrated refilling it. Some says its water pump problem. I have video of it. But couldn't find the option to upload it. Can anyone tell what might be the possible causes of coolant leak after the engine is shut off?

Asked by for the 2007 Mini Cooper
Is it still hot when it was pressure tested. Did you have it running while pressure testing, it can build pressure at shut down after driving, with a heating expansion issue allowing the leak. Just comments of things I have had to do. Create the same conditions that allows the leak while testing.
I got it pressure tested at Mini of Woodlands in Houston. The technician told, with engine switched on condition he tested for pressure for almost 1 hour. even though he was unable to fix the issue.(as mentioned in previous comments travelling 15-20 miles is equivalent to keep engine on for one hour rite?) but technician suggested there is oil filter leaking and it might stop if he replaces oil filter gasket. but he is not ready to guarantee the fixing and estimating about $939. I have uploaded a video in you-tube with title "Coolant leak after engine shut off in mini cooper".
Great watch the video. Will give some insight.
Qualified Local Mini Shops
Qualified Mini Shops For This Repair
950 Airport Rd # 301
Technical Ability
Tools & Equipment
Customer Service
Customer Amenities
(254) 255-4268