Expire is not really the right term; but effectively yes. In general a cheque older than six months will be considered stale-dated and will not be honoured. Reference the Canadian Payments Association FAQ.
SKYACTIV is a brand name for a series of technologies developed by Mazda which increase fuel efficiency and engine output. The initial announcement of the SKYACTIV technologies include new engines, transmissions, body, and chassis, which appeared in Mazda products from 2011.
Earth Dreams Technology. Earth Dreams Technology is Honda's latest generation of engines proving their commitment to fuel-efficiency and environmental impact. By enhancing Honda's original VTEC (Variable Valve Timing and Lift Electronic Control System) technology to further improve thermal efficiency and minimize friction, a new combination of high output and fuel efficiency was achieved.