Hi, all I remember about this film is that there is a supposed 'monster' in a lake but it ends up being some sort of truck that comes out at the end. Possibly late 70s, 80's movie. Cheers for any help.

Frog Dreaming (1986) (http://www.imdb.com/title/tt0091810/)

Cheers thanks a lot, that's it. Was clled the quest when I saw it, has a few titles. Thanks a bunch

You're welcome.