So today I was driving down the highway in my rig when a couple of girlies in a jeep pull up along side me all smiling and what not, and then not 30 seconds later my truck starts pouring white smoke so I pull over, how embarising haha. But back to the important part, I pulled over and it was running fine but I killed it immediately thinking I blew headgaskets again so I checked the oil and it was fine, so I crawled underneath to see if it was pouring out of a head, and what do I see? The block heater hanging out with the front axle. It appears that it unscrewed itself and fell out. Is this common? I hope I didn't hurt my motor I pulled over ASAP and my buddy behind me said it was comin out for about a quarter mile. The smoke worried me but I think it was falling onto the exhaust.