I'm getting worried about my bike

[Losidan]

My daily squeeze is a 2002 Marin Palisades trail I got off fleabay for £100. It has (touch wood) served me well over the last 18 months of my weighty frame riding on and off road.
Lately though it is making some very un-nerving noises. I seem to get a loud cracking noise from the rear wheel area when i get out of the saddle to give it some stick. I had it in the LBS who stripped and rebuilt the rear hub and said it was all good.
Still doing the same thing though....I am wondering if the freehub or cassette or possibly BB are about to give up the ghost?
Any ideas. Appreciate I am being pretty vague here but unsure what info you need from me for a Diagnosis doctor

 

[palinurus]

Might not be coming from the wheel. Bike clicks and creaks, as often stated on here, can be tricky to track down and can appear to originate from somewhere other than their causes.

The noise is only apparent when you apply a fair bit of pressure to the pedals, and out of the saddle.

Could be the BB (worn or loose?), chainring bolts? (any loose?), cranks (sometimes just taking them off, cleaning the interfaces and re-assembling works for me). Pedals?

But I don't know much about bikes, except how to bollocks the BB threads on my frames. Have a look here

Sheldon Brown on Creaks

 

[RedBike]

As above, this noice really could be coming from anywhere.

Your best option is to take EVERYTHING apart and re-assemble tightly with loads of grease. Do one part a day until you've found the creak or run out of parts to try.