K&N® 33-2181 - 33 Series Panel Red Air Filter (13.688" L x 5.188" W x 1.25" H)

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Product Details

K&N Air Filters

33 Series Panel Red Air Filter (33-2181) by K&N®. K&N's replacement air filters are designed to increase horsepower and acceleration while providing excellent filtration. K&N makes over 1,200 different replacement air filters for the majority of vehicles on the road. These filters are washable and reusable and are custom designed to fit into your existing factory air box. Their drop-in design means adding performance is simple. With most vehicles you simply remove the disposable air filter and replace it with a K&N. See applicable instruction sheet for details. K&N stock replacement air filters for street vehicles are covered by K&N famous K&N Million-Mile Limited Warranty and will be the last air filter your vehicle will ever need.

K&N - F.A.Q.K&N - Air Filter CleaningK&N - Warranty


Filter Types: Direct Fit Filter
Filter Shape: Panel
Filter Style: Non-Flanged
Filter Color: Red
Filter Outside Width: 5.188"
Filter Outside Length: 13.688"
Filter Height: 1.25"
Air Filter Material: Cotton Gauze
Filter Re-Oiling Amount: 1.21oz


  • Designed to boost horsepower and rate of acceleration
  • Can be cleaned and used again
  • High air flow with exceptional filtration
  • Lasts up to 50,000 miles before cleaning is required depending on driving conditions
  • Works with original equipment manufacturer vehicle electronics
  • Emissions legal in all 50 US states
  • Will NOT void vehicle warranty
  • Million Mile Limited Warranty®


  • 1 Air Filter

Most air filters on the market are a compromise. Many high-performance filters deliver better airflow, but sacrifice filtering ability and engine protection in the process. OEM filters, which are usually made of paper, filter adequately but at the expense of airflow. And airflow decreases as these air filters become dirty. Not so the K&N air filter. K&N air filters increase airflow without decreasing filtration ability, and the increased airflow remains consistent throughout the filter's service interval. The secret is in the K&N filter's construction.

K&N's initial goal was to develop a filter that would deliver increased airflow during dirty, dusty off-road racing conditions. Increased airflow improves the efficiency of the combustion process, increasing horsepower and torque. But just increasing airflow without ensuring adequate filtration under those conditions would result in a ruined engine. K&N's solution was a filter design consisting of 4 to 6 layers of cotton gauze sandwiched between two aluminum wire screens. The cotton is then treated with a specially formulated grade of oil that causes tackiness throughout the cotton’s microscopic strands. The resulting K&N filter not only delivers increased airflow while trapping dirt particles that could harm your engine, that level of airflow is maintained even as the filter gets dirty. The layers of oiled cotton fibers in the K&N filter trap dirt particles that are smaller than the holes in the filter media. The thickness of the layers also allows the K&N filter to trap dirt and dust on many levels, trapping more dirt without decreasing airflow. Contrast this with a paper filter that only traps dirt on its surface; as the surface area becomes clogged, the airflow rate goes down.

Each K&N air filter is custom designed to fit into your existing factory air box. The K&N filter is economical because it's the last air filter you'll have to buy for your car. It can be washed and reused many times, and since you can usually drive up to 50,000 miles between servicing, you won't have to clean it very often. And every K&N filter is backed by K&N's Million Mile Limited Warranty. By the way, check the CARiD reviews and read what the customers think of K&N porducts.

K&N® is the inventor and leading innovator of reusable cotton gauze filter technology for automotive applications. The first K&N filter was conceived for racing over 40 years ago and a performance enthusiast mindset continues today throughout all levels of the company. K&N is the sales and brand leader for performance filters, including an extensive line of factory replacement filters and performance air intake kits. The company actively promotes the environmental, economical and performance advantages of long-life reusable cotton gauze filters.

Part Number:

Warranty Information

K&N O/E Replacement Air Filters and Air Intake Systems purchased from Authorized Dealers are backed by a Million Mile Limited Warranty when used primarily on paved roads and on vehicles for which they were designed. If one of these products ever fails to provide complete satisfaction, K&N will replace it.

K&N Aftermarket Air Filters should be cleaned every 50,000 miles for normal highway use, more often in dusty conditions. Cleaning should be done with K&N cleaner and air filter oil (or comparable air filter cleaner and oil). Use of compressed air, or chemicals not specifically designed to clean and re-oil cotton air filters (i.e. gasoline, transmission fluid, motor oil, lightweight oil, or diesel fuel) will void the warranty. Any damaged, abused or modified K&N Air Filters will not be warranted.

Any K&N product returned to K&N will need a Return Goods Authorization number and must be sent at customers' expense along with proof of purchase.

Any defective K&N Air Filter properly returned to K&N will be replaced. K&N reserves the right to determine whether the terms of the warranty, set out above, have been properly complied with. In the event that the terms are not complied with, K&N shall be under no obligation to honor this warranty. K&N will not be responsible for any indirect, consequential, special, contingent, or other damages.

K&N wants to make sure that when you buy a K&N Lifetime Air Filter or Air Intake System, you can be confident your vehicle's warranty will not be impacted. K&N also want you to feel confident that even if you experience difficulties with a dealership repair department, K&N will step-in and resolve the issue, so you won't have to. Therefore, K&N makes the following Pledge: K&N pledges to their customers that they will not be taken advantage of and charged for a repair due to a manufacturer warranty denial blamed on the presence of a K&N product.

Magnuson-Moss Warranty Act:
Legally, a vehicle manufacturer cannot void the warranty on a vehicle due to an aftermarket part unless they can prove that the aftermarket part caused or contributed to the failure in the vehicle (per the Magnuson Moss Warranty Act (15 U.S.C. 2302(C)) Learn More

Vehicle Fitment

2015 Mercedes G550 
2014 Mercedes G500 / G550 
2013 Mercedes G500 / G550
  • 5.5L
2013 Mercedes S400 
2012 Mercedes C Class
  • 3.0L
2012 Mercedes G500 / G550 
2012 Mercedes GL Class
  • 4.6L / 5.5L
2012 Mercedes GLK350 
2012 Mercedes S400 
2012 Mercedes SL550 
2011 Mercedes C350 
2011 Mercedes C300
  • Gas 3.0L
2011 Mercedes CL500
  • V8
2011 Mercedes CLS550 
2011 Mercedes E500 
2011 Mercedes E550 
2011 Mercedes E350
  • 3.5L
2011 Mercedes G500 / G550 
2011 Mercedes GL Class
  • 4.6L / 5.5L
2011 Mercedes GLK Class
  • 3.0L
2011 Mercedes GLK350 
2011 Mercedes ML500 
2011 Mercedes ML550 
2011 Mercedes ML350
  • 3.5L
2011 Mercedes R350
  • 3.5L
2011 Mercedes S400 
2011 Mercedes S500
  • V8
2011 Mercedes SL500 / SL550 
2011 Mercedes SLK300 / SLK350 
2010 Mercedes C350 
2010 Mercedes C300
  • Gas 3.0L
2010 Mercedes CL Class
  • 5.5L V8
2010 Mercedes CLS550 
2010 Mercedes E350 / E500 / E550 
2010 Mercedes G500 / G55 AMG
  • 5.5L
2010 Mercedes GL Class
  • 4.6L / 5.5L
2010 Mercedes GLK Class
  • 3.0L / 3.5L
2010 Mercedes ML500 
2010 Mercedes ML550 
2010 Mercedes ML350
  • 3.5L
2010 Mercedes R350
  • 3.5L
2010 Mercedes S400 / S550 
2010 Mercedes S500
  • V8
2010 Mercedes SL500 
2010 Mercedes SLK300 / SLK350 / SLK55 AMG 
2009 Mercedes C300 / C350 
2009 Mercedes CL500 / CL550 
2009 Mercedes CLK350 / CLK550 
2009 Mercedes CLS550 
2009 Mercedes E Class
  • 3.5L / 5.5L
2009 Mercedes G500 / G55 AMG
  • 5.5L
2009 Mercedes GL Class
  • 4.6L / 5.5L
2009 Mercedes GLK Class
  • 3.0L / 3.5L
2009 Mercedes M Class
  • 3.5L / 5.5L
2009 Mercedes R350 
2009 Mercedes S500 / S550 
2009 Mercedes SL500 / SL550 
2009 Mercedes SLK Class
  • 3.0L / 3.5L / 5.5L
2008 Mercedes C230 / C280 / C300 / C350 
2008 Mercedes CL500 / CL550 
2008 Mercedes CLK350 / CLK500 / CLK550 
2008 Mercedes CLS350 / CLS500 
2008 Mercedes E350 / E550 
2008 Mercedes G Class
  • 5.5L
2008 Mercedes G500 
2008 Mercedes GL Class
  • 4.6L / 5.5L
2008 Mercedes ML350 / ML550 
2008 Mercedes R350 / R500 
2008 Mercedes S500 / S550 
2008 Mercedes SL500 / SL55 AMG / SL550
  • 5.5L
2008 Mercedes SLK Class
  • 3.0L / 3.5L / 5.5L
2007 Mercedes C230 / C280 / C350 
2007 Mercedes CL500 / CL550 
2007 Mercedes CLK280 / CLK350 / CLK500 
2007 Mercedes CLS Class
  • 3.5L / 5.5L
2007 Mercedes E350 / E550 
2007 Mercedes G Class 
2007 Mercedes GL450
  • 4.6L
2007 Mercedes M Class
  • 3.5L / 5.0L
2007 Mercedes R350 / R500 
2007 Mercedes S500 / S550 
2007 Mercedes SL500 / SL55 AMG / SL550
  • 5.5L
2007 Mercedes SLK Class
  • 3.0L / 3.5L / 5.5L
2006 Mercedes C230 
2006 Mercedes C280 / C350 
2006 Mercedes C55 AMG
  • 5.5L
2006 Mercedes CL500 / CL55 AMG 
2006 Mercedes CLK350 / CLK500 / CLK55 AMG 
2006 Mercedes CLS500 
2006 Mercedes CLS55 AMG
  • 5.5L
2006 Mercedes E350 
2006 Mercedes E500 
2006 Mercedes E55 AMG
  • 5.5L
2006 Mercedes G Class
  • 5.0L / 5.5L
2006 Mercedes ML350 / ML500 
2006 Mercedes R350 / R500 
2006 Mercedes S350 / S430 / S500 
2006 Mercedes SL Class
  • 5.0L
2006 Mercedes SL55 AMG
  • 5.5L
2006 Mercedes SLK Class
  • 3.0L / 3.5L / 5.5L
2005 Mercedes C240 / C320 
2005 Mercedes C55 AMG
  • 5.5L
2005 Mercedes CL Class
  • 5.0L
2005 Mercedes CL55 AMG
  • 5.5L
2005 Mercedes CLK Class
  • 3.2L / 5.0L / 5.5L
2005 Mercedes CLS500 
2005 Mercedes E320 / E500
  • Gas
2005 Mercedes E55 AMG
  • 5.5L
2005 Mercedes G Class
  • 5.0L / 5.5L
2005 Mercedes ML500 
2005 Mercedes S Class
  • 4.3L / 5.0L / 5.4L
2005 Mercedes SL Class
  • 5.0L
2005 Mercedes SL55 AMG
  • 5.5L
2005 Mercedes SLK350 / SLK55 AMG 
2004 Mercedes C240 / C320 
2004 Mercedes CL Class
  • 5.0L
2004 Mercedes CL55 AMG
  • 5.5L
2004 Mercedes CLK Class
  • 3.2L / 5.0L / 5.5L
2004 Mercedes E500 
2004 Mercedes E320
  • Gas
2004 Mercedes E55 AMG
  • 5.5L
2004 Mercedes G Class
  • 5.0L
2004 Mercedes S430 / S500 / S55 AMG 
2004 Mercedes SL500 
2004 Mercedes SL55 AMG
  • 5.5L
2003 Mercedes C240 / C320 
2003 Mercedes CL Class
  • 5.0L
2003 Mercedes CLK320 / CLK500
  • Coupe
2003 Mercedes CLK500
  • Convertible
2003 Mercedes CLK55 AMG
  • 5.5L Coupe
2003 Mercedes E320
  • Sedan
2003 Mercedes E500
  • Sedan
2003 Mercedes E55 AMG
  • 5.5L Sedan
2003 Mercedes G Class
  • 5.0L
2003 Mercedes S430 / S500 / S55 AMG 
2003 Mercedes SL500 
2003 Mercedes SL55 AMG
  • 5.5L
2002 Mercedes C240 / C320 
2002 Mercedes CL Class
  • 5.0L
2002 Mercedes E500 
2002 Mercedes S430 / S500 
2002 Mercedes SL500 
2001 Mercedes C240 / C320 
2001 Mercedes CL Class
  • 5.0L
2001 Mercedes G500 
2001 Mercedes S Class
  • 4.3L / 5.0L
2001 Mercedes SL500 
2000 Mercedes CL500 
2000 Mercedes G Class 
2000 Mercedes S Class
  • 4.3L / 5.0L
2000 Mercedes SL Class
  • 5.0L
1999 Mercedes CL Class
  • 5.0L
1999 Mercedes G Class 
1999 Mercedes S Class
  • 4.3L
1999 Mercedes SL Class
  • 5.0L
1998 Mercedes S500 

Product Reviews


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K&N® - 33 Series Air Filter
K&N® 33-2181 - 33 Series Panel Red Air Filter (13.688" L x 5.188" W x 1.25" H)
Average Rating: 4.5 of 5
4.5 of 5
Great Filter for Any Engine
K&N® 33-2181 - 33 Series Panel Air Filter
I purchase these filters on all of my vehicles (past and current). I had lots of gas savings on my Toyota Highlander 2005, about 60 miles per tank more with K&N, but with 2008 model I didn't have any difference. But the ease of going up to speed was better with K&N in it. On the current Mercedes ML350 I felt a good change in acceleration as well, haven't tested MPG yet.
APosted by (Jacksonville, FL) /
2010 Mercedes M Class
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