Change spark plugs strictly by mileage?

[eggsalad]

2017 2.5 NA CX-5

Not quite to 50k miles on an 8+ year old car. At the current rate, I won't achieve the 75k spark plug change interval until the plugs are 12 years old. That seems a long time. Should I change plugs sooner, or wait for 75k?

 

[ADS-B]

If you feel the need to replace the spark plugs, just go for it. No need to wait for the 75.000 miles mark.

 

[Mazdiod2]

Are you having any driveability issues? Do you drive a lot of short trips and idle the engine a lot? If you idle the engine a lot you might be fouling the plugs without logging miles, so there is that to consider.

If you drive the car about 80mph on the highway for several hours it can help. Otherwise, it's ok to change them if you want, but the manual says 75k and I don't think there is a time limit on the plugs.

I've got about the same miles on my 2016 and I'm just going to wait another 4-5 years.

 

[shooter357]

The replacement of the plugs in the book is a recommendation only. The more mileage on them widens the gap making it harder to jump and placing a small strain on the electronics.

 

[Jmaz]

I changed mine at the 10 year and ~71,000 mile mark using the NGK plugs. Even though the original plugs looked good and the gap was basically unchanged, the idle became smoother and the throttle response improved. Glad I changed them. It was also a good time because I changed the valve cover gasket first because of a small amount of oil leakage around the base of #1 spark plug.