More wierd noises

[andy400]

Really bad 'clicking noise'. Only happens now and then, starts quiet, gets louder, then goes away until the next time. Next time can be anything between 10 minutes and 10 hours later. I did think of some ideas but thought that most would make that noise constantly not just occasionally.

Any ideas?

[parrot of doom]

Speedo clicking every 1/10th of a mile?