I changed the air filters on my 2007 ML CDI to K&N from paper elements. Is this a problem for the MAF? I was warned against the K&N as it may short out this sensor? It does on other TDI vehicles like the Volkswagen. thanks for any advice.

 

I had to take them off my car because they kept throwing the MAF

 

thanks, it seems to be safe i will switch back to paper elements.

 

I have been running them for the last 53k miles with no problems.I clean and re-oil them twice a year ( spring and fall ) and have had zero problems.

 

NEVER had a problem with a K&N filter. I use them in all my cars. But, I also don't think you gain anything for the $$$ over stock filters.

 

Just had some feedback from K&N that may be of interest to other users and readers. specifically regarding the MAF.
Dear Valued K&N Customer,

Thank you for your interest in K&N products. No Computer adjustments are required during the installment of a K&N Air Filter, once installed, you are ready to drive. K&N oil treatment on our cotton is very small (usually less than 2 ounces). Once the oil is properly and evenly absorbed through the cotton, no oil will come off, even under extreme engine conditions. It is ridiculous, because no dealership or service provider has ever been able to provide us with evidence to support this "myth," and in fact, our investigations have revealed that even authorized dealerships are simply speculating and do not have the test equipment necessary to know whether the sensor has failed or why. It is even more ridiculous because some car manufacturers use and sell air filters treated with oil on a regular basis. There are also major brands of disposable air filters that are treated with oil. We all use oil for the same reason; it helps in the filtration efficiency of an air filter. For more information on this topic including videos, see our Mass Air Flow Sensor Statement page: http://www.knfilters.com/MAF/massair.htm .

 

I have used K&N filters for years on my cars with no problems, until I used them on my CLK55. Car went 100k miles on the stock MAF/regular filters with no problems. I put in the drop in K&N filters and have gone through 3 mafs in 10k miles. I put regular filters back in, and have gone 10k miles without a problem...I won't be using them again on a merc.

 

Thank you for your story. I was in the same boat with my new Chevrolet truck a couple of years ago. I too changed back to the paper filter, and my truck is now at 230,000miles. The fact about K&N filters is they are more expensive, don't give you ANY improved performance, and have NUMEROUS user complaints specific to MAF failure. On a truck, the MAF is a couple hundred dollars....I couldn't imagine on a Mercedes.

The fact that K&N calls our claims "ridiculous", or some "myth" as shown in the letter from capyaincook. There's a very strong correlation between K&N filters and MAF failure. For everyone in the world that's had a trouble free 100k miles on their K&N car, great. Realize there are just as many people that have experienced trouble. MAF's don't just go out, they aren't a part that should be cleaned or serviced.

Will K&N ever acknowledge their troublesome filters? Probably not. You're stuck with the dealership bill. It's really too bad these get hyped so much by places like Autozone. "Come spend money on all these parts to see improved performance and fuel economy!!"....

 

I used to install K&N air filters in all my vehicles. Never had a single problem putting them in Jspanese brands or a Hyundai. Put one in a 99 Audi A4 1.8T, it didn't like it and killed the maf. Ordered a K&N for wife's new Jetta Tdi, but read on Tdi club they were having horrible luck with them, so returned it. So from my experience over the past 25yrs, Japanese/Korean cars put one in. German makes, stick to Mann disposable air filters.

 

What are you trying to gain by using the K&N?

If the aspect of purchasing a filter only once and clean/re-use is the purpose you have to balance this against the expected time you will keep the vehicle... i.e. a 3 year lease & turn back the vehicle won't pay for the investment. Keeping the vehicle for 10 years & 200,000 miles probably will.

If you are looking for a performance or mileage gain you will be disappointed. The air box itself is the greatest restriction - no single filter has improved the flow or lowered dP.

I personally use the K&N's on my off road/severe duty applications. There they seem to have some merit. I don't use them on stock applications or the daily drivers since their cost is greater than their benefit for my driving.

 

I never did change back to the paper element as we left on a 2000 mile road trip soon after the switch.
Now, about 7000 miles later on the K&N and there have been no issues. Thanks for the report and yes i plan on keeping the ML for many more miles and years. Apart from regular service the ML has been a remarkably trouble free vehicle. Still great mileage considering its weight and no rattles after 100 K miles.

 

K&N air filters are wrong for many reasons. But lets start with filtering. If you read K&N's website and you bogosity filter doesn't peg, I feel sorry for you. "Snake oil" salesmen. If one could make an air filter filter as well or better with less restriction then the world would beat a path to your door. K&N's key patents are long expired, so now Fram (who has never passed on a snake oil concept) has cloned the K&N for themselves.

Place a smear of grease inside the clean side of your airbox. Use a K&N. Check the grease. Ask yourself if you are happy at the grit you find in the grease? Repeat with paper air filter. I don't think you will put a K&N in anything ever again.

Today K&N says they have never heard of a MAF failure due to their product? Way too many MAF failures are occurring on K&N equipped vehicles for coincidence. Not too many years ago K&N boasting they had soaked every major manufacturer of MAF's sensors in K&N oil with no failures, clearly they have heard of K&N related failures. Check the clean side of your airbox, why is it soaked in K&N oil? It is K&N oil. It is on your MAF sensor. MAF sensors are sensitive to contaminants.

Consider the claims of more HP and MPG. On a gasoline engine air + fuel = power. You control the air with your right foot. Engine ECU controls the fuel to match your air. What happens with less restriction in the air filter? Nothing but you raise your right foot. Same amount of air gets to the engine. Same amount of fuel. Same amount of power. What restriction your air filter does not provide you make up with your foot. The only time less restriction in the air filter might help is at full throttle. Spend much time at full throttle?

Economy of washable air filters. With paper filters you pop the old out and the new in, and off you go. The K&N has to be washed. And dried. And then oiled. And the oil needs to dry. Perhaps you can do half tonight, half in the morning before work. At $7/hour minimum wage you start losing money pretty quick. I use oiled foam filters on my dirtbikes. Spend a lot of time on air filters. I keep spares to rotate in and out of service so I can immediately install a clean oiled filter when I take a dirty filter out. Otherwise its something one has to start one day and finish the next while the vehicle is out of service.