K&N in Mazda3s
 

My dealer said that an oil-charged filter might kick my "check engine light" on, and to get it to turn off, an expensive process would be necessary. As the purchase of my 2007 M3GT Hatchback progressed, I steadily lost faith in the dealer. So I'm suspect as to the advice I was given concerning a switch to a "standard" K&N filter. Does anyone have experience with Mazda3's and K&N air filters?

It could gunk up the mass airflow sensor, which would just require pulling it off (near your air filter) and cleaning it (carefully, it's very expensive and delicate).

See if AEM makes a "dryflow" filter for your car. I'm sure there are other dry performance filters out there.

I used a K&N filter in my Pro for over a year without issues. Unless the intake system is vastly different, I wouldn't see a problem.

K&N says no problem
 

I just received this response to an inquiry I sent to K&N concerning oil from their filters and its effect on the mass airflow sensor:
__________________________________________________ ______________
K&N has experienced rare instances where dealerships and/or repair
facilities "blame" damage to a vehicle's Mass Airflow Sensor (MAF
sensor). The dealership's most common unsubstantiated claim is that K&N
oil contaminates MAF sensors, causing them to fail. The truth is, OIL
DOES NOT COME OFF the K&N air filter. K&N has conducted extensive
testing at both its own testing laboratory and at an independent
forensic laboratory. To date, we have never found a situation where a
K&N air filter has caused a problem with a MAF sensor. Unfortunately,
this truth does not stop dealerships from making absurd claims.

Please clink on the provided link to read more information on this.
http://www.knfilters.com/MAF/massairpledge.htm

If you have any further question please call our Customer Support Team
at 1(800)858-3333 and an agent will be happy to assist you. Thank you
for writing and have a great day.

Thank you for choosing K&N!

Sherri Sykes
Customer Service Rep
1(800)858-3333
sherris@knfilters.com

Oil does come offthe filter, that's an obvious lie. Must I take pictures of the inside of my intake piping near the filter? The red 'indicator' die K&N puts in their oil proves that it isn't a blown oil seal on the turbo or something else causing it.

ive had my K&N typhoon intake for around a year now. never had a check engine light, and the Mass airflow sensor is plugged in too. not sure if it was oiled or not..

I had a K&N in my airbox for over a year. When I took the airbox out to have a look, Didn't look oily to me, not even dirty really. MAF sensor looked fine when installing the CAI.

I had a K&N for my RX-7, and I would say that it is possible for oil to come off it, but only if you apply too much. That is the biggest variable in a K&N filter, because its maintainance is done by the vehicle owner, and improper cleaning and/or re-oiling could result in problems. Some people might have a 'more is better' mentality when oiling the filter, and that is definitely not true.

I have a K&N Typhoon intake in my 3 for about a year, and never a any CEl or problems.

If you do get a CEL, all you need to do is unplug the battery and it will clear it. But this doesn't clear the error code stored on your ecu. For that all you need is someone with a OBD2 scanner and he will clear it in no time. Not complicated at all. You can even buy the OBD2 scanner on ebay.

I've had K&N filters in pretty much all of my cars and never had an issue with it setting off a CEL

Like Khoney said.. most people over-oil them when they clean it... very little oiling is needed.. if you put too much on.. you're actually going to affect the flow of the filter.

Also... doesn't mazdaspeed sell a Cold air intake with a cone filter? This would be the same as having a K&N filter. If they sell a product that they don't recommend for the car... I would say they have problems

I would say.. if this happens to you, the CEL comes on and you have a K&N filter installed.. just put the stock air filter back in before you take it in to get checked.