Since the 4 cyl engine is direct injection, I have heard of potential carbon buildup on the intake valves. I would like to know if this engine has experienced this problem and what might be done to avoid the problem.
I assume this is “Skyactiv-G” engine and YES indeed it is direct injected (DI) one.
Carbon buildup is not really plaguing Mazda DI engines of this series, but they do recommend cleaning up valves every once in a while, something like 50K miles.
To reduce deposits, use only good gas and good oil, that will do
Cleaning up valves - is that a DIY process?
This product was developed to address this issue.
I’ve used this Sea Foam Spray on my 2013 Chevrolet Equinox with the 2.4 4 cyl DI engine twice (30k and 60k miles). I’ve had no issues before/after each treatment. To be on the safe side I only used about 1/2 the product for each treatment. I consider it preventative maintenance. It has 79k miles and runs fine.