K&N effects on gas mileage and MAF damage
Junior Member
Joined: Jun 2008
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From: santa barbara
clk 63 black series
4 years ago I bought brand new pair of K&N's for my Brabus engined CL500 & I noticed a mileage drop & found they had "coked" my MASensor = $291 - I installed myself. SO Be Careful
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Corrolla
Senior Member
Joined: May 2008
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From: San Francisco
Sold - CLK500
i just spoke to cory at renntech.. and yes dont try to correct me.. there is a cory at kleemann too. he told me to avoid k&n's they are not designed for mercedes. The oil leaks from the filters onto the maf and causes issues.
however, he did recommend green filters which i will be getting very soon along with a renntech airbox
however, he did recommend green filters which i will be getting very soon along with a renntech airbox
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Joined: Oct 2006
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02 C32 AMG
i just spoke to cory at renntech.. and yes dont try to correct me.. there is a cory at kleemann too. he told me to avoid k&n's they are not designed for mercedes. The oil leaks from the filters onto the maf and causes issues.
however, he did recommend green filters which i will be getting very soon along with a renntech airbox
however, he did recommend green filters which i will be getting very soon along with a renntech airbox
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Joined: Feb 2004
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From: NY
2014 E350 4Matic
My green filters fell apart around the edges. I'm so disgusted with the co. that I havn't even bothered to get it to replace them yet. Some on the board claim that the manufacturer of green filters has changed the rubber compound they use and the filters no longer disintegrate. Who knows?
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Junior Member
Joined: Nov 2009
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SLK230 '98 CLK500 '06
feel free to correct me, but seems to me that the only time reduced airflow because of filters would effect mpg or hp would be at or near wot. otherwise airflow is restricted by throttle position not filters. even at wot my guess would be throttle body is the limiting factor. as long as filters breathe better than throttle body, there should be no tangible effect of using a less restrictive filter. since the service life of oem stock filters is considerable, the danger of using substandard, or unapproved oil coated filters, to me seems an undesirable choice. i think K&N variants have been out there long enough that MB would be using them stock if they were actually an improvement. MB is constantly trying to push hp [amg] and fuel economy, yet neither MB or AMG, or any other tuner suggests the use of these [snakeoil] filters.
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Joined: Oct 2007
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From: SoCal
98 Brilliant Silver E320 Wagon
Hardly anyone argues this issue any more on other sites. My personal experience -
When I got my E320 W210 wagon about 2 1/2 years ago, I thought I might save some money by getting a K&N reusable air filter. I check my mileage every tankful (the old way). Over a period of a couple of months I saw my around town mileage go from 18.5-19.0 to 16.0-17.5. I pulled the K&N, cleaned the MAF sensor, installed an OEM paper filter and the mileage improved on the very next tankful. Bosch will point out that the more porous K&N will allow particles which will actually pit the surface of the sensor. This will eventually cause enough damage that the MAF sensor will need to be replaced.
But I understand many people want to have fun with their car and gas mileage and replacement costs aren't very high on the priority list.
When I got my E320 W210 wagon about 2 1/2 years ago, I thought I might save some money by getting a K&N reusable air filter. I check my mileage every tankful (the old way). Over a period of a couple of months I saw my around town mileage go from 18.5-19.0 to 16.0-17.5. I pulled the K&N, cleaned the MAF sensor, installed an OEM paper filter and the mileage improved on the very next tankful. Bosch will point out that the more porous K&N will allow particles which will actually pit the surface of the sensor. This will eventually cause enough damage that the MAF sensor will need to be replaced.
But I understand many people want to have fun with their car and gas mileage and replacement costs aren't very high on the priority list.
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From: Colorado
AMG V6/V8 Kompressor cars use a speed-density metering system=no MAF sensor, so those engine's have no problem using K&N's. NASP 112/113 engine's don't have problems with K&N's as long as their not over-oiled. As soon as you put a supercharger on a N/A 112/113 (where you're sucking 30-50% more air through the air filter at a higher velocity), any filter that requires oil becomes problematic. MB employs hot-film air mass sensors- This film is heated to a constant temperature. As air travels over the film, the temperature of the film is reduced, and requires more voltage to keep it at a specific temperature- the voltage requirement is directly related to the volume of air traveling through the MAF housing. Even getting a tiny amount of oil on this film will cause the sensor to drift out of calibration, which won't necessarily turn on a CEL. No amount of CRC cleaner is going to help either, since the oil becomes baked onto the film due to the heat. If one lets it go long enough, it will eventually burn a hole in the film and you'll get a code for MAF short circuit to ground or open circuit.
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Joined: Oct 2007
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From: SoCal
98 Brilliant Silver E320 Wagon
The operational temperature range for the Bosch Type HFM-5 sensor used in MB 112/113 engines is -40C to 120C. I don't think modern synthetic lubricants will 'bake' to dryness at that temp. If so, then the oil on the cylinder walls would be giving us all major headaches.
Anecdotal data is what it is but over the past several years I have read many posts regarding cleaning MAF sensors in these engines in which the results were successful. One point may need mentioning. You must remove the insert in order to clean the sensor. And, of course, some people may have cleaned temp resistor thinking that was the MAF sensor.
See attached Bosch Document, pg. 3-4 Type HFM-5
Anecdotal data is what it is but over the past several years I have read many posts regarding cleaning MAF sensors in these engines in which the results were successful. One point may need mentioning. You must remove the insert in order to clean the sensor. And, of course, some people may have cleaned temp resistor thinking that was the MAF sensor.
See attached Bosch Document, pg. 3-4 Type HFM-5
Junior Member
Joined: Mar 2010
Posts: 33
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From: Middle of the Pacific
2017 E300
The operational temperature range for the Bosch Type HFM-5 sensor used in MB 112/113 engines is -40C to 120C. I don't think modern synthetic lubricants will 'bake' to dryness at that temp. If so, then the oil on the cylinder walls would be giving us all major headaches.
