koalatm

Hi everyone,

I couldn't find any sort of guide on replacing the engine air filter for the GLK 250 so thought I'd just mention a few notes here given that I had to figure it out on my own.

First, it's a pain in the ***. I've installed cold air intakes, short rams, etc... this ranks up there with some of the most difficult air intake installs I've done, and this was just a replacement filter!!

I replaced the factory filter with a K&N as it was the only one I could find online that shipped to Canada. Would recommend AEM dry flow, but they don't make one for this vehicle.

Our GLK only has 30,000 km and the stock filter was DIRTY. I've never, ever had an air filter that dirty after 30k.

http://www.knfilters.ca/search/product.aspx?prod=e-2998

Unfortunately I didn't take pictures as I went - I was too frustrated to do so

1. Remove the plastic engine cover. Flat head screw driver at the front centre of the cover pops the plastic holder, and then pull the cover towards the front of the vehicle to disengage from the two prongs at the back side of the engine
2. You'll need a torx screwdriver - preferably with an extension as a few of the screws are in tight spaces
3. There are 6 torx screws on the airbox lid, 2 at the back, 1 on each side and 2 easy to spot ones at the front
4. 5 of the 6 torx bolts are fairly easy to get to. The one in the back left (closest to the front passenger door) is a nightmare.
5. To access this PITA torx screw, you'll probably want to release the clips holding the wiring above this spot, so that the cables can be gently moved aside allowing a bit better access
6. I only had a cheap torx set that attached to a rachet, so it was tight for me - a proper torx screw driver would fit a lot better
7. Once you have all 6 torx screws loosened (do not pull them all the way out, they should stay attached to the airbox lid if you're gentle
8. Move the lid back, and stand it up on end, voila the air filter is finally visible
9. To remove the factory air filter, wiggle it up and down, away from the front end of the vehicle and it'll pop out
10. Be nice to your GLK and give everything inside the airbox a nice quick wet wipe down - mine was beyond dirty
11. New filter just pops right in, make sure you wiggle it as tight and as far forward towards the front of the vehicle as you can
12. Reverse the order - that torx screw in the back left corner will come back to haunt you again when you re-do everything.
13. Make sure you re-clip the wiring if you moved it out of the way like I did
14. You're done!

Alex Bel

Thanks for details.

Do you think filter for $34.95 from idparts will be OK?

http://www.idparts.com/catalog/produ...oducts_id=3893

koalatm

Yep for sure that filter is fine. Thanks for the site link, I didn't know they existed.

The K&N is probably better value if you'll keep your GLK for a longer period of time. If you said you needed to change the filter every 20,000 miles, at 100,000 miles you've spent $175 on the Mann filters, and $135 on the K&N.

Alex Bel

My 2014 GLK250 does not require new engine air filter yet, but at the time I've researched the K&N filter for GLK was not available. All my cars have K&N filters installed and I'll do it for my GLK when time comes despite the higher price. And thank you for the K&N air filter item number. Now I know what to buy in the future.

koalatm

How many miles are on your GLK? I did this at the equivalent of 20,000 miles and the filter was dirtier than any air filter I've ever had on any vehicle.

Alex Bel

So far less than 15,000 and I think I'll check it in the summer...

MBKLUE

Are you saying you think the standard filter is not good or that you do not want to replace it so often?

formerjeepguy

The oil used by K&N is proven to foul MAF sensors, they do not filter as well, they cost more, and cleaning them is tedious. I'll stick to stock or MANN filters.

Here are a few links to help you decide:

http://forums.automobilemag.com/70/6...you-thousands/

http://www.nicoclub.com/archives/kn-vs-oem-filter.html

http://www.bobistheoilguy.com/airfilter/airtest3.htm

koalatm

I'm not saying the standard filter is not good, I'm saying that mine was very dirty after 30,000 km.

In other vehicles I normally change the filter every 20,000 km or once per year, whichever happens sooner. On the GLK I did the opposite (1 year, instead of 20,000 km) - as I couldn't find a replacement filter here in Canada other than the dealer asking $90 for the OEM one.

Yes, K&N can foul MAF sensors. It's vital that you do not over oil the filter. Cleaning them is very easy, I've had a few K&N filters over the years- going back to my first car in 2000.

As I said, I'd run AEM dry flow but they don't make one for this engine.

MBKLUE

"I'm not saying the standard filter is not good, I'm saying that mine was very dirty after 30,000 km."

Not trying to be a smart-*** but you do understand that a dirty filter is dirty because it stopped that dirt from entering into your engine, right? A "cleaner" air filter would concern me. Simple "math."

noahw

I believe there are 7 torx screw not 6 as mentioned.
The seventh is at the top centre holding the filter in place.
The 6 are at the corners and 2 at the mid ends:


x x


x x
x
x x


Looking from the top. Bottom torx screw at front


Tough to find those back screwa as they are under some harness.

koalatm

Thanks Noah, I'll take a closer look when I open it up to clean our K&N filter. I can't recall there being a screw at the top centre but you could very well be right.

noahw

Just for clarity, the top centre torx screw holds the filter to the cover.
The filter cover has 6 torx screws that you clearly discussed as being
tough to locate.
My drawing shows that the torx centre screw is at the side.
It is actually at the top centre, just in front of the silver box.
If you look at it you'll know what I mean.

ovistana

Your model is USA ?
If yes the k&n filter will not fit properly.

koalatm

It's listed as compatible and given that I've done the install I'd say it works perfectly.

ChrisJo

Good morning to all,

Tried to install K&N air filter in a Canadian GLK250 yesterday afternoon and it didn't fit. The filter front part (round) fits well over the intake at the front but the rear of the air filter is too thick to allow the air filter housing lid to close properly. The screws at the rear will catch a little if the lid is held down but will not seal properly.

By the way, the seventh screw, center screw in the housing lid goes thru the air filter and screws on the bump(post) at the bottom of the housing, hence the fact it is a little shorter.

Back to fit... the thickness of the rear K&N filter at the half moon shape end is too great, 3/4 in thicker. I removed the electronic module from the lid, 2 X E10 (etorx) removed and slide module forward and it becomes obvious that the K&N is too thick.

I contacted K&N customer service and sent email with pics and they are looking into it? whatever that means. I'm awaiting a solution for a proper fitting filter.

More to follow...

koalatm

Chris - I have a 2014 Canadian GLK and the filter fit 100% perfectly without any issues. Make sure you wiggle the front of it onto the attachment point as far as you can - if you don't get it far enough, it won't clear all of the housing at the back end, which is probably the issue you're having.

Unless they shipped you the wrong part number? Which part did K&N give you? The one I used was E-2998.

ChrisJo

Tried again to fit the K&N air filter into the housing and close it to no avail. This time I removed all the metal clips and the square electrical connector clipped to the air box lid. Inserted the K&N air filter into its place and pushed it forward as until the flange contacted the plastic stop in side the housing. My issue isn't that the length as the K&N fits into the housing length wise but it is too thick at the fire wall end. As I was trying to fit the K&N filter in, I received the following email from K&N Technical Support Agent;

"After reviewing this fitment with the product manager the air filter E-2998 is listed for Non-US vehicles; this refers to anywhere in North America and since you are located in Canada, the vehicles are made according to the US standards. So unfortunately, this air filter will not fit your vehicle application and there is not an alternative we could provide you with at this time."

So, I rest my case. I also posted a few pics to show the thickness difference between the filters. If I install the K&N and screw the lid back on the housing, there will be a 3/4 inch gap left at the back of the housing.

I'm returning to the MAHLE LX 1833-00 until K&N tells me they can provide a correct fitting unit.

koalatm

Very interesting. It literally fit mine 100% perfectly.

I threw out my factory air filter of course but it's too bad as I'm really curious now to see how thick it is in relation to the K&N.

Was the extra thickness preventing you from closing the airbox lid?

ChrisJo

Hi,

Yes, extra thickness partially because of the tab (pic) at the rear inside the housing designed to hold the original filter but also because of the ribs inside the lid which makes the lid much sturdier. I took some measurements to see if eliminating the tab (cutting it off) would allow me to close the lid and screw it in completely but it wouldn't. I'm not sure if trimming the ribs would give me enough room either for the K&N so I removed it and put the OEM (MAHLE) back in.

Also notice how the filter body on the OEM is offset from the round fitting you slide on the air intake and the K&N is centered. This also tells me there is a right way and a wrong way to install the OEM"

thetonka

I need to weigh in on this. I come from a diesel truck background and spent a number of years building up my F350 to pull a large toyhauler. As an engineer I did LOTS of research.

I have always used K&N filters on my cars, until I got a diesel. I will still use K&N on normally aspirated cars but after doing research I will not run them on forced induction. The problem isn't even the MAF, it's the turbo, specifically the vacuum created by the turbo. As the turbo spools up it creates pressure in the intake, but what happens before the turbo. Significant amounts of vacuum. This can and does suck the oil out of the K&N filter dramatically reducing its life. Once the oil is gone they do not work very well. The oil is key to proper performance of a K&N.

K&N on a normally aspirated engine, not much risk. K&N on a forced induction engine, significant risk. It is risk though, so make your choice accordingly.

polobai

FYI, after reading this thread and a few others saying that it would not fit US models, I bought one and installed it. The filter is substantially thicker-but I was able to get it in and the lid to close securely with no issues. I didn't have to cut off the tab or do any modification. This may be worth noting-our glk 250 was a European Delivery but I am pretty sure it's us spec.

koalatm

It really does fit just fine. We just had it in for the 60,000 km service, which includes a lot of stuff... I had a new fuel filter and brake fluid change done at the same time. The shop didn't say anything about the K&N filter being an issue for them to take out, inspect, and put back in.

WolfgangGullich

/bump

K&N filters can seriously damage emissions systems of clean diesels. If that MAF gets fouled, it can effect the cleaning cycle timing which can end up costing $$$...be really careful using any oiled air filter with a modern clean diesel

koalatm

Oh well. Most of us will not keep the vehicle long enough for these issues to actually present themselves.

If aFe Power ever released their dry flow filter for this application, I would switch to it.