The oil doesn't actually get thicker- - - -it stays at the 25 weight viscosity all the time- - - -it just lubricates like a 60 weight when it gets hot. Worrying about engine damage from "thick" oil is a big waste of emotional energy. Run the stuff and be happy with it- - - -the engine won't care!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!