Can any gas powered vehicle need to have valves ajusted as they age and what causes valves to need to be adjusted?
If you have mechanical lifters like Hondas and some older vehicles use, the valves need to be adjusted periodically per manufacturer's recommendation. Most engines though have hydraulic lifters that do not require adjustment, or use steel shims to control valve lash which rarely if ever get out of adjustment.
Oh thanks do you kno which one my 2012 fusion 4cyl has
I'm not familiar with that engine. You might want to check on a forum specific to that vehicle:
https://www.fordfusionforum.com/
Scotty has said that the only cars he's seen that really need regular valve adjustments are Hondas because they use an old-school adjustment mechanism, and that others either use hydraulic lifters or have shims that rarely need adjusting. Best to check on the needs of your specific engine though.
Technically, all need to be adjusted.
The reason valves need to be adjusted is that they hit the valve seats in the head thousands of times and sit deeper into the head, thereby decreasing the specified valve clearance to rocker arm, and hence, need adjustment.
