They held us at the gate Sunday 6:05 am flight because of this problem.  Think they're cutting corners. We waited for 2 hours while they "fixed" a frozen engine, on a plane that originated in Anchorage. They waited to start the engines when passengers were aboard rather than earlier.  I too have flown for over 45 years and never seen this before.  Alaska Air needs to pay more attention to the SEA-ANC route.