In the past, I might have agreed . . .
with you re quick warmup. Before I changed my tstat, it would take a relatively long time to warm up which appeared ok!
But after changing it, you could see that the old tstat would not fully close, open about a 1/8". Thus the engine would take a longer time to warm up: that's maybe ok for SoCal but probably not good for any other place.
The replacement tstat does the same as yours: very quick warmup so don't think there's anything wrong.
But would advise the use of MB af and distilled water if you haven't in the past. Consider a good flush before refilling. And try the 40/60% mix (af/water).
Regards . . . . JimF
'94 S500 Cpe
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