Engine clicking noise about 2300-2700 rpm

I am hearing an engine clicking noise in a 98 SL2 A/T with 128Kmiles on it.
Seems to happen around a certain rpm (over 2000, about 2500 rpm), whether
car is parked or moving, and independent of gear. There also may be some
temperature dependence: seems not noticeable in cold engine, but in warm
engine.

I got this car 20,000 miles ago, so don't know history.

Auto parts store advice was to use oil additive (CD2) on the idea that
metal parts (valves, lifters) are gummed up, and got severe warning to keep
eye on oil. (I do lots of highway miles and change it about 4000 miles,
but did notice one time it was more than quart low at half the mileage!
Hope I am not paying for that mistake!)

Can anyone describe sounds/symptoms (and if it is rpm-dependent) of timing
chain problems in Saturn engines?

 

I am hearing an engine clicking noise in a 98 SL2 A/T with 128Kmiles on it.

I would start by taking the accessory drive belt off and starting the engine.
Only run it very little, remember, without the belt you have no water pump. If
the noise is still there then you know it's something internal. However, its
very likely the noise is coming from a belt driven accessory such as the
alternator.