Hello, I was driving on the highway when I suddenly saw, in my review mirror, white smoke escaping from the engine lid. I immediately stopped, but it was already gone and I smelled nothing special. I drove further but it didn't happen again.
Has it done it since? I'm thinking it must be steam or else you would smell something. White smoke from exhausts is steam head gasket if grey smoke then oil overfill if it goes away or very rarely white smoke can be break fluid leaking into the vacuum system and ingested by the engine... It's not using break fluid is it....long shot but you never know. Smoke from the engine bay that doesn't smell and goes away suddenly....a leaking water hose that fixes itself? not likely.. Mmm
I was going to suggest looking at the power steering fluid cap, but that would be on the 't' only. (The gasket around my cap broke and allowed ps fluid to drip on the manifold periodically. Easy fix but irrelevant to your problem, unless you have another reservoir in the engine bay that may have lost its cap gasket)