Sorry in advance if this is the wrong section or been posted in the past. I was backing up a travel trailer yesterday at home when my wife yelled at me that there was something leaking. I got out and looked and there was coolant leaking out coming down the driver side kinda by the front drivers tire. It leaked out on to dirt so it was hard to see the colour. I parked the trailer and then opened the hood and the engine coolant holder was 2-3 inches below the cold fill mark. Iam the farthest thing from a mechanic but am 99% sure its coolant. It has not leaked anymore since parked. Im not sure if this is just wierd timing but we towed the trailer home today about 40 miles for the first time ever with this truck. ( The truck is a 2008 f150 with the 5.4 and a tow package). So I guess Im looking for some advice what to do or what the problem might be. I tried to get under the hood and find a leak in the hose but no luck. I was going to fill the coolant back to normal level and monitor it. Also what colour antifrfeeze should I use.

Thankyou