Symptoms of Valves that need adjusting
Scheduled maintenance
Many cars have valve adjustments built into scheduled maintenance, for a fairly simple reason. Adjust the valves before they’re terribly out of line, and you’ll never have to deal with valve issues.
So, pay attention to the scheduled maintenance. The manufacturer is trying to help you save some money and hassle.
Tapping noise
A tapping or ticking noise under your hood means two things: First, your car may need of a valve adjustment, and second, you probably didn’t pay attention to the scheduled maintenance.
When the valves aren’t properly adjusted, there will be a weird tapping-like noise due to the inaccurate spacing.
Engine performance problems
A valve adjustment that’s either too loose or too tight can lead to engine performance problems such as rough running and lack of power. Either scenario can cause damage to the engine as well.