DDAnimalzz

Has anyone here used a K&N air filter and had problems with the oil in the filter messing up their MAF Sensor?

I didn't purchase the K&N air filter for the supposed bump in HP. I could care less about the 1-2 ponies that they advertise. I just want an air filter that will do the job and not (supposedly) screw with my MAF sensors and cause a whole host of other problems.

I'm looking for first-hand experience. Not, stories you've heard second-hand or read on other forums.

Moviela

I put them in my Mercedes. It made it louder, but the mileage went down because the factory "pre-oiling" coated the glass bead of the MAF sensor. It was simple to clean with the CRC MAF cleaner sauce. I also had an issue with the seal around the perimeter of the filter not sealing the outside air from the intake. The K&N did not have as "poofy" a seal as the Mann filter it was designed for.

I have run the stock Audi filter on my A4, and you can run a white gloved finger down the intake and it comes out clean. I don't think any other filter will do a better job than that.

K&N filters are fine for racing, because the engine is going to be "gone through" with only a few hours at most on the Hobbs. I think oil bath filters were fine in the forties, but with modern materials and manufacturing a paper filter makes more sense on your street car.

QUA77R0

I have run K&N drop in filters in a number of cars over the years. From A to V... as in AMG to Volvo turbos.

Never had any problems with them out of the box. In fact my AMG mechanic who is the shop foreman at the local Mercedes dealer recommended them over stock. He told me that the only problems he has ever seen with AMM sensors was after a user cleaned and re-oiled their filters (we have 2 airboxes on the E55). He said that problems arise when the filters are over saturated with oil. He suggested that once I hit 60k, I just toss the filters and put another new set in. Considering that I have only put 21k on the E55 in 11 years, I doubt whether that will happen in my lifetime...

On the factory turbocharged cars that I have run K&N drop-ins on, I have always found an oily film inside the intake regardless of whether stock or K&N filters are used. On the Volvos, I never cleaned or re-oiled them... Never had any loss in power nor did I notice any change in noise level. But those had thermally insulated airboxes so maybe they dampened the sound. On the Mitsubishi 4G63's that I ran K&N drop-ins on I did clean and re-oil on both after runs in the desert where I was sure that I had picked up plenty of dust. Never had any intake issues. Don't recall whether there was any change in noise on those but they weren't exactly quiet to begin with. If I recall correctly, they used MAP sensors not AMM's so no possibility of coating the sensor as an issue.

If you are going to use paper, stick to MANN OEM filters like moviela said. They are far superior to any of the other paper OTS junk found in most auto parts stores.

That said, I am "guilty as charged" by moviela's description since most of my street cars have also seen track time at one point or another. I look at it as the only responsible and safe way to see what they can really do without risking anyone's well-being or a chauffeur driven ride to the nearest holding cell. And yes I understand being on a track is a risk. I don't mind calculated risks and feel safer on the track where I can predict the actions of the drivers around me with a much greater degree of accuracy than out on the road. Leaving a track to head home is when I really feel at risk...

Best regards

DDAnimalzz

Thanks for the informative responses.

Are MANN air filters the OEM part that's in the 2010 A4?

If so, would you happen to have the part # handy?

If not, do you know who manufactures the OEM part?

a4-bob

While I don't have first hand experience, I did look into this as the OP is and decided to stick w/ OEM filters. I found some test results online that showed K&N filters passing much larger particles through and clogging up faster than oem filters. K&N allowed more airflow initially but as they clogged they allowed less airflow than the OEM filter over the same period of time.

To me, the gain did not justify the cost, maintenance & possible trouble from allowing extra crud through.

DDAnimalzz

What brand is the OEM filter?

av_audi

I never understood the attraction to K&N filters in normal applications. Sure, in extremely dirty environments it may maintain airflow longer, but we are talking about the duration of dirt road races here. In normal applications, where we drive tens of thousands of miles between filter changes, that becomes a completely irrelevant advantage IMHO. The stock filters smaller particles, but if you are worried about reduced airflow near the end of the filter change interval, just change it 10K sooner. We are talking about a $20-25 part here.

av_audi

That's true, but I am starting to hesitate to continue assuming that anything from Mann/Mahle/etc. will be as good as OEM. I just bought a Mann fuel filter that was made in China. That per say doesn't mean anything, but you wonder whether they have cost cutting in mind for their non-OEM marked lines.

Huey52

Nay. Have used them and find too much noise for too little enhanced filtration/airflow. The lifetime use, if properly cleaned/oiled, is attractive, but I rarely did so more than once. Stick with OEM and just change more often if desired, imho.

DDAnimalzz

Sorry to ask this again, but does anyone actually know where I can find this OEM air filter?

Does it have a brand name that I can search for or do I have to purchase this directly from the dealership?

Thanks!