The operating temp is probably the same as before. I think the illusion is based on my increased scrutiny.
It normally operates around 95 degrees.

Again I tested it from cold start. No noise whatsoever for quite a long period while 'cool'.

Once it gets to operating temps, that subdued noise is apparent from the water pump body.

Correcting my own previous observation, the noise at issue is not a clear metallic sound but more like a subdued or muted sound 'as-if a hardish object is rolling around in there'.

I am now hoping that it merely is the sound of hot coolant gushing around, although I have never noticed such 'noise' before.

Anyway, I plan on monitoring and will update. No seeping coolant on garage floor.

That is good !

Thanks for everybody's help.

__________________
1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
********************
1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD