Saturday I decided to take out my MAF and give it a cleaning. Didn't clear the code, so I'll have to replace it, but now that I know what I'm doing it doesn't scare me in the least.

So here is my quick write up with childish annotations.

1. Get open the hood.


2.Remove the front intake tubes, if you pull them toward you they will come right off, no drama necissary.


3. I've read horror stories about people breaking the clips while removing their engine covers so I took particular while removing, and thought I'd share my method that worked quite well.

Lift up at the front, and watch it till the shroud clears the oil fill cap. Once it clears, pull it straight toward you. It should come off quite easily. if you feel like it isn't going to clear the oil fill cap without breaking, then remove the cap, but make sure to put a rag in the hole to keep debris from falling in.


4. Remove the rear part of the shroud, this is the piece that contains your air filers, and directly interfaces with the MAF and by extension the intake. Just pull up on the front, and once that is loose, pull up on the back.


Now you're engine compartment should look something like this


The piece you are looking for is in the back right smack dab in the middle. It looks like this.


Or from the other side.


If yours is anything like mine, than this little bugger will be the bane of your existence for quite a while. I hope that my explanation of how to get this off will save you from the fate that I had.

Looking at the following two pictures, you will see how the connector connects. Understanding this is the first step toward eternal happiness.



Even thought it goes against everything your previous experiences have told you, push down on the two clips, and pull it firmly out. Using a wiggle motions while doing so may hurt your reputation at the biker bar, but will make this task a lot easier. I did that AFTER I un-seated the MAF because I couldn't figure it out before, now that I understand the connection I won't have to do that again.

The two arrows in the picture are the clips that hold the MAF to the manifold. I removed them by hand.


After these two clips are released, take this hose, and move it to the other side of the hook type holder.


Rotate the MAF backward while reaching behind to release the metal clip on the back. (Sorry couldn't get a good shot of it)

Should look like this once out, Congrats, you've just removed you MAF!



And once it's out you'll be confused as I was that this little thing could cause so much trouble.

Nicely done. It’s too bad the cleaning didn’t clear that pesky code.

Nice writeup. It's really easy to do once you've figured it out. I wonder how detrimental that zip tie is because mine fell off last time I took the MAF off and I've yet to replace it.

Yeah, I was bummed about that too, but I can get another one for $150+40 core. Now that I've done it once I know I can do it easily (even in the hotel parking lot!) without tools. So maybe I'll get that done this week. Hopefully that will help my gas mileage.

I forgot to replace that when I put it back in! It snapped coming out. All it does is ensure that the ring doesn't un-lock.



So I can't see it doing anything terrible. I'll replace it when I put the new one in.

mskembo, the gasket on your oil filler cap is leaking oil. Replace that gasket, it's about $2. If you go to the dealer for this gasket, they'll try to sell you the entire cap and gasket; you only need the gasket.

Thanks PCY, I was gonna call them about that today. Now I won't get taken!

mskembo, in the 11th picture you've posted, it looks like you are missing the lock pin for the cap of trans filler tube. If you've purposefully left that lock-pin out, then put some tape on the cap to prevent dust going into the dipstick tube. Otherwise, get a new lock-pin. It's about $1 on-line. Can't be much more at the dealer.

This is what you'd need...

That zip-tie ensures the clips on the collar ring (for the MAF) stays put. With that zip-tie off, it doesn't take much effort to break that collar ring with clips. I don't want to find out how much MB charges for that piece of plastic. :-)

Wow, thanks for catching that! That's why I love this forum, so much information, I never would have caught that without you saying something. Just another part to get at the MB dealer today.

Maf cleanin should be the last thing u should do haha. Get a rag and clean that engine bay..

I beleive he has diferent kind of cap with no lock-pin.

Ontmiss, he was right, if you look at the other picture it's down below the MAF. I already picked up a new lock-pin, and will install it when I get back to my hotel tonight.

Xhale, that's just mean... I took the trouble of taking delightful pictures (hopefully providing more clarity to others than I had when I started this task), and all that I've gotten is mocking, and people pointing out how ugly my car is ON THE INSIDE. I'm taking my ball and going home.

BTW, Just kidding, I know there isn't any hate meant.

ontmiss, the picture you are referring is the OIL dipstick tube. There is nothing wrong with that cap - his car has electronic oil monitoring sensor, no dipstick. Hence, the cap.

I was actually referring to the TRANS fill tube cap - refer to picture # 11 in mskembo's original post.

You know, I think I'm just going to post random high resolution pics of my car on here from time to time just so people can tell me these little things. It might make me feel better!

Nice writeup. The M272 cars are VERY similar in assembly as well.

Sorry guys, on my engine 272 transmission tube is right there and for engine oil is on front. BTW I bought 5 lock pins at dealership $1.25 each.

Nice man. Is it worth it to check this if I don't show any codes for it etc... ?

Periodic cleaning of MAF is a good idea - assuming you don't break the MAF in the process of removing and cleaning :-) It's a delicate electronic device inside. Treat it accordingly and don't poke inside with screwdriver or anything.

dang it... I got ripped off then.

just got me the tranny dipstick tool so I went to my local stealership to pick up the lock pin.

they charged me $2 a pop... bought a few just so I won't have to drive all the way back to the stealership if I popped it off again.

kinda stupid they call it a "lock" pin.
talked to a tech about it as I was curious as to how they lock.
he basically told me it's more of a seal then a lock.
just something MB cooked up so they can tell if you messed with the tranny in the first 4 years of it's life. (hence why you can't get the black ones)

anyway, back to the MAF cleaning.

I wish the MAF was that easily accessible on the M271... dang you MB!

good job OP!

It's a pin when inserted in to the cap, it locks the cap. Hence, the name 'lock pin'. When you open the cap, you should see an o-ring/seal. So, that lock-pin is not a seal.

On-line places sell that lock pin for less than a dollar like 65 cents or something. Whenever I order parts online, I usually throw in stuff like this - lock pin for trans fill cap, oil filler cap gasket, gas cap gasket, oil drain plug gasket, trans drain plug gasket, etc.

I went to the dealership yesterday, and bought a new lock pin, and since they didn't have the oil filler cap gasket in stock I went ahead and splurged for a new oil filler cap ($12)... but now I'm trading my car in, so I don't know why I did even that.

bah!

I think you can drive without the lock pin and I don't think the cap will pop off.

but you are right. it does "lock"... but as it was explained to me by the tech, only secondary function to it's main purpose.

sly, cleaver MB engineers...

where can you get the pins for 65 cents? both autohausaz and rmeuropean have them for $1.20-1.30 range...
Thanks.

Please take a look at the following picture.
Part # 41 is an o-ring. This is what SEALS the cap to the tube.
Part # 40 is the cap. It's purpose is to COVER the fill tube opening.
Part # 42 is the lock-pin. It's purpose is to ensure the cap doesn't come off. This lock-pin ensures the cap is pressed against the seal and the fill-tube. The cap hugs and stays with the seal when the lock-pin is inserted. Again, the lock-pin is locking the cap to the fill tube.

Not having the lock-pin doesn't mean the cap will come-off. Not having the lock-pin leaves a small hole in the cap; dust may go in, albeit small amount.

I was wrong about 65 cents for the lock-pin. I thought that's what I paid last time when I bought.

not arguing with you PCY.

tech's point was:

MB could have made the cap like the one on the oil "dipstick" tube.
locking pin was not necessary. it's main purpose was to give indication to the techs when they work on the car, to let them know if the tranny could possibly been messed with by the owner or indi while under warranty.

fair enough statement?

I pretty much got the jest that I could put tape over the hole and drive with it without the lock pin and it would be fine.

again, not arguing with you. it was a point the tech brought up that I found interesting.
I appreciate your contribution to the forum and your knowledge.