I have been bothered by the engine noise a few months now. Seem to have interval on every round rubbing and a few clicks once in a while. The sound is not that pronounce but can be heard from near and inside. Does not come from upper part but from the belt side. Check timing belt condition, still in good condition but will change once problem is diagnosed so that all work will be done at once.

Compression resulted to an average of 170 per cyclinder.
Would compression test reveal any bearing problems? camshaft? crankshaft? or possible other parts like ac motor or pulleys?

Car has 131,000 miles. Turbo.
A few days ago, engine started to show intermittent idle but dissapears lately and runs normal.

Does that this means that engine is about to go? or simply changing comprehensive t-belt change would fix the problem?

Would appreciate a knowledgable or a master mechanics' advise on these matter.

Thank you!