hubert

Did anybody changed the air filter on their bluetec GL. I want to replace the oem paper filters with K&N but looked under the hood and it does not look so easy. I see the the filters are on both sides on the back of the engine and there is no clips just 8 screws total on both filter covers. Three screws are no problem but how do one unscrew the rear botton ones ?

lkchris

K&N filters are garbage quality wise and provide ZERO performance adantage combined with the risk of destroying your mass air sensor--not warrantied when it happens.

In addition, change of air filter on diesel Mercedes requires computer reset.

Fourdiesel

And you want to do this why?
See the following quote from a part of a Drivbiwire post (he is one of the most technically knowledgeable members on any diesel forum):
"-OEM air filters replaced ACCORDING THE SERVICE GUIDES, Never replace early since a reduction in filtering efficiency will result. Then again the OEM filters have less restriction than any aftermarket gimmick filter! So far I have measured a maximum pressure drop on the OEM filters of only 3 hPa...Cipher that into inches of hg and you will see how well they outperform any filter system."
If you have actual technical data (and NOT from K&N) that shows the change is warranted we all would be interested and would like to review the numbers.

rich4368

I bought the Mann filter (same as the original) for my 2010 GL350 a few weeks ago still haven't got time to replace. I saw the four screws from both sides and don't think can get to the last twos. What about ply open and force out the filter with one screw still intact? Will that break the cover? The other route is to remove the bars on top and take out the air intake in order to access to the fourth screw, which is lots of works.

hubert

Dont try to force them out as the cover might brake!!! i spoke to my dealer and the next time im there they will replace them for me as a part of my maintenance... So nobody here replaced their paper filters with a washable one likr K&N???

L8Apex

Hubert:

Thought I would revive your old thread. Changing the air filters to the K&N replacements is fine if you dont want to modify the stock filter.

As FourDiesel mentioned, the paper "element" is good and performs very well. However, the stock filter is restricted on the driver side can be modified without damaging the filter. (see attached picture below)
So, the simple solution is to replace or modify the filter or replace it with one that is not restricted. Although I prefer BMC filters the K&N version work just fine but allows more dust through. I modified my stock filter in less than an a half hour..this includes a beer break.

Driving impressions: The only way you can tell the K&N filters are installed is by a slightly higher pitch of the turbo under boost. It is nearly impossible to tell if there is a performance difference on a big heavy truck like the GL. Is the K&N or modified version it worth it? For me yes.. I would much rather be turning a wrench and modifying something in the garage than rearranging my sock drawer. For me, I went the modified route and removed the black restrictor.

If you would like a step by step instruction on how to remove and replace the filter assemblies just let me know.

hubert

The step by step instructions with pic would be great. Thank You

MRAMG1

Well, I can tell you that you are dead wrong about K/N's my friend. I have used them for almost 30 years now with GREAT success.

Now, for these particular cars, I did use them on my GL450, with not so good results. After only 5-6K on them, my idle started breaking up, and the car would respond poorly. My MB mechanic came out to the waiting room and said in his words "K/N's do not work well with the MAF on this vehicle"

He cleaned the MAF, put stock filters back in, and the car runs great again.

Now, for the interesting news.

I contacted K/N, and they were VERY respectful and apologetic.

I e-mailed the invoice for the filters, and the service visit.

In LESS than 1 week, I received a check from K/N for the original purchase price, AND the service visit.

They paid for BOTH!!!!

Now that IS customer service.

Would I use K/N's again, you bet!!!

Just not on this car, LOL

alx

i have them in all my vehicles- including my cdi gl. they do work and over a longer time span they will offer some savings.

regarding removing the air intake assembly- do search the forum. it requires removal of strut brace and some blood and gore. satan is in there too when you are reinstalling and trying to get the intakes to mate properly.

it can be done.

however as i said a while ago in the past engine adaptations need to be reset via das when replacing air filters on the cdi. otherwise you risk messing up the service a/b vs c selection by the computer as well as some performance advantages (supposedly)

L8Apex

The only reason I would not use the K&N on a turbo vehicle is due to the amount of particles that get through the cloth...especially if I planned on keeping the car for awhile. Why? The MAF issue doesn't bother me as much (clean it or wipe away the excess oil on the new K&N) as the dusting effect the particles will have on the impeller of the turbo over time. If you plan on keeping the car for a few years than this isn't an issue.

Install instructions:

-Remove engine cover
-Remove the vent cover for the cabin filter.
-Remove upper strut brace. (#12 Female Torx)
-Loosen the 2 corners of the firewall over hang (clearance to remove the filter boxes) (10mm wrench)

Passenger side airbox:
-Loosen flathead screw for rubber boot connected to airbox towards turbo.
-remove front bolt and loosen rear bolt do not remove out of box housing (#6 Female Torx)
-Lift airbox straight out
-Loosen the 4 torx screws (#3 torx) and remove filter element.

Driver side airbox:
-Remove 3 bolts holding reservoir tank directly infront of airbox and plastic tie holding cable on top of reservoir. This step is to provide clearance to remove airbox. (note the shape of the bolts for reinstallation)
-Remove air sensor on top of airbox (#3 torx screw (i think)
-Loosen flathead screw for rubber boot connected to airbox towards turbo.
-remove front bolt and loosen rear bolt do not remove out of box housing (#6 Female Torx)
-Loosen the 4 torx screws (#3 torx) and remove filter element.

Reinstall in reverse order. Took me a total of 30 minutes.

Traveling right now so cant post pictures. Will do so later. Hope this helps!

ballanr

Sorry for the late reply (only 3 years)

Your instructions were clear however pictures would help alot. If you have time can you update the instruction on how to change the Air Filters on a GL350 with some pictures.

Also I am getting a "Front side marker bulb" warning on my dash but when I check all the bulbs they are all lighting. I purchased new bulbs from NAPA and the bulbs for the "Front side marker" are clear but when I follow the MB manual the bulbs depicted are Amber?

So seem to be very knowledgable. Any ideas?

will_w204

When I was young and dumb in my VW days, I bought into the oldtimers trying to sell their Amsoil/Snakeoil/K&N/Crap filter du jour, and several aiflow meters and a couple grand later, I learned that you can indeed buy an expensive filter, buy their filter oil, hand wash said filter every few thousand miles, and re-oil it as many times as you like, while you replace said airflow meters, hear some extra intake noise you wouldn't hear with a stock filter, and pretend that you are getting extra power from all that hype.

Do yourself a favor. Use the stock paper filter and change it when the element turns gray. Save your money for things like replacing the peeling window trim, or the fading plastic appliques