I seem to have a rather strange problem with my mk2 172 (another one!). Every now and then I get this random sort of ticking form the dash board, it seems to come from behind the sppedo or just to the right of it. I have had the dash off and had a look behind it but I cant see anything that it could be (I though it could be a leaf stuck in the vent).
The noise is really random, and not that frequent but when it does do it it does it for about 5 seconds and then stops!
Any ideas as to what it could be?