Anyone heard of an issue putting a K&N air filter in a 2012 Mazda 5? When I took mine to the dealer for it's first service, I asked about this and they told me not to. Apparently, the filter messes with an oil sensor and one of the questions asked for a faulty oil sensor is whether a K&N air filter is installed. They went on to say that the filter will void the warranty and the sensor runs about $800 (US). They also said that K&N is aware of this issue and that it is the case on other makes and models. What gives?

 

I was thinking K&N also but I don't think you'd benefit with performance nor cost over the long haul in you compare it to a regular paper filter. Not to mention the hassel of cleaning then re-oiling the filter. Save yourself the headache and get a bunch of paper filter and put good synthetic oil in the car for a slightly better ride and longevity.

 

As dieseldriver2003 said, save yourself the headache (and the money); a K&N won't do squat for your performance or fuel economy, it's a pain in the hind parts to maintain, and as your dealership informed you, it can have sensor reliability and/or warranty implications as well.

 

The concern your dealer mentioned was the MAF sensor getting oiled, which is certainly not a good thing to have happen. From the factory (pre-oiled) it would be fine, but most people tend to over-oil the filter element when servicing the filter. That's where the trouble lies.

That said, and having used a K&N panel in my 3 series for a about a year before installing a CAI, I agree w/dd2003 and shipo. Don't waste your money or your time.
You can buy 4-or 5 paper filters for the cost, not have to worry about oil bleeding on the MAF, not have to clean/dry/re-oil/wait the filter every 10-15k and your performance/mileage will not change either way.

 

Thanks everyone! If the gains, or lack of them, from the K&N aren't worth it, then I'll just stick with the paper filters. Appreciate the responses!

 

Ditto on the oil versus MAF. You can invest in a higher quality paper filter.
WIX Filters : Filter Look-Up

 

I am using a K&N Filter without issue. There is a procedure for cleaning it, letting it dry properly after cleaning, then re-applying oil, letting it soak in properly and wiping it off with a rag or paper towel. It only needs to be cleaned every 2-3 years. By then you should also clean your MAF anyway, as well as your throttle body!
However, spending extra $$$ on a good quality paper filter would be safer for those not familiar with K&N's proper cleaning procedure or those not familiar with proper procedure on cleaning the MAF (which is extremely easy).
This is a great comparison of many brands: K&N air filter or OEM, why OEM is better The K&N is worst on catching dirt (96% efficient) and has the least restriction for maximum flow.
You'll have to decide whether you accept small microns in your engine and better flow, or no microns with still adequate flow (but gets dirtier faster restricting flow and more frequent changes).

 

Having increased air flow doesn't really mean better performance, once the optimum ratio of fuel/air reached, any more air simply means more dirt/particle. I think with newly designed ECU and engine, modern cars can be operated under wide range of air flow without server damage, but if the dirt/particle goes into the engine, the increasing wear will happen