coolant loss

I discovered a large pool of coolant the next morning after a 60 min drive from base. Couldn’t locate the leak topside. Couldn’t find a leak around the reservoir. Drove it a few more times with no issues. Found this another 4x in the last 2 weeks. I only find the pool after it’s turned off...

Hi everyone, I have a 2016 3.5 ecoboost and am losing coolant fairly rapidly. I noticed it about a month ago when my truck was not heating. I checked coolant and it was very low. Added coolant and about a week later it was an inch low. Took it to service shop, did block test and everything...