50,000 miles ago (at 100,000 on the speedo), the chain tensioners were replaced. 'Twas obvious that at least one had failed, for whilst driving along, (listening to Madonna at high volume as I recall), when the cassette in the Blaupunkt ended, the car itself carried on the music's beat with a relentless "rat-a-tat-whap-whap-whap": loud and embarrassing to boot!
Now nearing 150,000 miles, I've just begun to notice a subtle chain whirring sound. If outdoors I cannot hear it. But 'tis become noticeable when driving in an indoor parking garage at low revs. It is not loud whatsoever. (I assume I cannot hear it at higher revs as the engine note itself drowns out the whirr, else its pitch is too high for human ears to detect).
Might this be the commencing of chain tensioner failure after another 50,000 miles? Or something else, related or otherwise? I gratefully await reponse from you experts
. Best.