yes, temperature could be a factor.
I keep my lens on the lens board in my pocket in a baggie when I shoot out doors in the cold.
The grease/lube inside is probably gunky, so like Francois said, taking one apart is not for the weak and you really need to right tools for the job-spanner wrench.
Just warm it up a bit and see if it gets happier.
Good luck! Gotta keep the Crown family working here!