Schnellfahrer

Am I wrong to assume that when the Clogged Air Filter light is not on the air filters are still clean enough and do not need replacement yet?
It is my understanding there are 2 air filters and that replacing them is not really a DIY job as they're hard to get at and the MAF sensors require recallibration after filter replacement.
Suggestions and advice are greatly appreciated.

DubVBenz

The air filters (both cabin) are super easy to replace. Just google instructions and purchase them yourself

Schnellfahrer

Thanks DubVBenz.
I am not talking about the cabin air filter which is indeed very easy to replace.
The ones I am refering to are the two air filters on the BlueTec. I'd replace them myself it were not an overly complicated DIY job, which I read it is. Especially w/ the recallibration of the MAF sensors.
So my question is can I assume that the air filters (not cabin filter) are still usable and don't need replacement as long as the clogged air filter symbol does not show on the instrument panel.

samaritrey

It is not a hard job at all probably takes 20 minutes as you have to get your torx sets out and some extenders to get at the two bolts per side.
You take off the intake piece that connects both sides to the turbo then two bolts on each air filter assembly and they pull out with some wiggling.
I recommend changing ever 20K or so as it has been said that a clogged air filter can cause excess oil going through the turbo and possibly even cause the famous oil cooler leak. I don't know anything about a light warning you to change them and even if there was one i would do a physical inspection every oil change anyway.

I just did the oil cooler fix last week and when I checked the air filters was shocked at how bad they had gotten with only 30k on them and think that might have been why it was leaking so bad. So if changing your air filters early can prevent the hell I went through I would do it once a month if needed lol but yeah check every oil change and be ready to replace ever 20k.

As for recalibrating the MAF I haven't done that and haven't noticed any issues and have put about 300 miles on the car since.

dgiturbo

Never had the MAF recalibrated ever. 153000 miles on the CDI. Can't recall if anyone has done this after a A/F change. I change mine every 20000 miles, and they are very dirty. You will be surprised at what this engine tries to suck in.

Air boxes come out and the filters are replaced on a workbench. Take your time, remove what ever is in your way to make room, and be careful with the wiring harness. It is a DIY job. Also do the fuel filter while your at it.

efzauner

I have changed mine twice. Manual says every 40K miles. It gets easier with practice! You do need torx bits and extender to get in the back. I suggest a good mirror light to see what you are doing.
The MAF sensor is supposed to account for variable airflow, including clogging filters.
I believe that you have to recalibrate if you change the MAF sensors.


I drain the fuel filter at every oil change and change the fuel filter every second oil change.. or about 20Kmiles

Schnellfahrer

Thank all of you guys for your good advice. As a shade tree mechanic I've learned a lot about these air filters in a short time. I am now the proud owner of a set of OEM filters which I hope to install this weekend. I do have a T25 star tool but it is way too big to get into the narrow crevices around the filters. I guess I'll have to jury rig a handle onto a T25 bit.
Btw. Samaritrey, a picture of the clogged A/F warning light can be found on p. 367 of the 2008 manual.
I see you guys also drain the fuel filter which I've never done. I have replaced the F/F twice by the dealer, a place I try staying away from as much as possible. I guess I'll start a new post on that in order to learn more on that subject. Thanks again everybody.

samaritrey

Cool never noticed that before after seeing how clogged up mine were to trip the light it must have to be almost competently closed off.

Plutoe

I have no idea where you read or heard about recalibration of the MAF,after changing out the engine air filters, but that information is wrong and misleading--the bigger problem is that other less learned folks will read the OP and pass on that very bad information---read your manual or preface your posts like--- I read at kiddy benz or my girlfriend thinks---that way folks will know its a pie in the sky thing.

Regarding your rinky-dink procedure to drain the water filter separator, find someone with WIS locate documents AR4720P07930MA or 94CWD(depending on VIN) and do the job correctly.

Regarding the engine air filters, if you want to do the job correctly you have to adapt the new filter to the car(amount of air, delta P bla bla)--this is done with Star---if not you will be whining about poor gas mileage/performance.

Read your owners manual before trying to do what you might think is simple maintenance

efzauner

Someone's dinky is all rinkly me thinks.
Draining the water from the fuel filter is simple. For my R320, (yes plutoe, I have WIS and read ar47.20-p-0793oma for my model)
The procedure calls for attaching a hose/tube to the drain pipe on top of the black drain knob/valve... and with ignition on to activate fuel pump, open the valve and observe the fuel draining into a container until there is no water left. I only recall having water once right after I purchased my supposedly certified pre owned... never once since. I don't bother with a hose, I just hold a cloth to the drain hole... there is not much fuel that comes out.


As for resetting using Star, well I gather it is the procedure "Reset quantity mean value adaptation data using STAR DIAGNOSIS" In theory yes, as the engine management system stores current value status and adapts from there. If you don't reset it will take a few miles to re-learn the new value instead of starting from zero.
Plutoe, do you know what happens if we don't reset? Never heard of issues with this in the 4 years I have been on this forum.

Plutoe

Well efzauner, now that you have had a WIS epifiney, maybe you should go back and correct your post 6 with the real story!!

With MB's I do my best to follow the factory procedure. I don't likle taking the same hill twice, gets expensive and I suspect(guess) that in this case the ECU will self adapt after ten drive cycles, however before that time I suspect that more fuel will be consumed.

N4HHE

The efficiency of a diesel depends on its ability to breathe. If you wait until things are bad enough for the idiot light then you have waited too long.

Log your fuel usage. When MPG starts down check the air filters.

On diesels with particulate filters (DPF) MPG drops about 10% as the filter fills with soot. Then falls through the floor for a brief spell when raw diesel is dumped to burn the soot out.

Plutoe

I have a minor opposing point---I trust the mfg engine design and their engine management software and do not preemptively replace parts just for the sake of changing---my belief is that when the light goes off that's when you change the filters.

Regarding fuel mileage not gas mileage that is one big circle jerk--nobody drives there car as if it was on a test bed--that's why the word estimate is important.

However like all things consumers do not behave the same---thank goodness, but you have my rational for why I am on the opposing side of this argument!!

N4HHE

Be sure not to check your oil until the oil idiot light is illuminated because clearly the engine management system knows better than the dipstick!

As with the low oil idiot light, the air filter idiot light does not, can not, trigger until bad things are happening.

You say you trust the manufacturer? The manufacturer says "replace every 20,000 miles." The idiot light is only there for exceptional situations such as a bird in the intake or a flock of locusts. Or mice building a nest.

I agree a dirty air filter is not hurting anything other than performance. And that the one performance metric available for mere mortals to measure is MPG. For the past 40 years MPG has always been a reliable forwarding of coming issues. Nothing has changed. Some noses are too high in the air to log fuel and calculate MPG, afraid someone will call them "cheap". Fine, its their loss not mine. For those people we have idiot lights.

On vehicles with a more knowledgeable ownership a spring loaded analog gauge is attached to the intake side of the air box. An electrical connection is also present to trigger the idiot light but otherwise one can open the hood and look directly at the gauge to know just how blocked the filter. Likewise one can replace the filter and see the difference on the gauge. Ford Powerstroke.

efzauner

Plutoe has such a lovely way with words! At least there are some golden nuggets to find!


Nobody is perfect, not even the Uber Engineers in Stuttgart!
The appearance of warning lights is not the way to maintain a car. Some may even be faulty. I get "check oil level", "check coolant level" and even a "low break fluid" level warning that where all false negatives... I can imagine false positives too where something is wrong and the warning light does not tell you!

Plutoe

I agree with you that nothing is perfect.

If you want to read up on the communication standards you will see the software provisions for the imperfect sensor world!!

As for your false +/- my point is/was that if it occurs very frequently--you do something about it and some will change all the fluids while others may try to find out why first----I am of the group that try to find out why first

N_Jay

So explain how a system that adapts to changes in the filter over its life would not adapt to a new filter without assistance?

Plutoe

Read up on the use of 0 and 1 within engine management software development--or alternatively ask your plumber why water does not come out of a faucet when the valve is closed!!

N_Jay

I'll discuss it with the consulting engineer who designed this;
http://www.harley-davidson.com/store...ance-tuner-kit


And I plumbed my own house.


Your credentials?

Plutoe

I am happy for you, however you did not understand my analogy.

My analogy does not have anything to do with plumbing a home or business or SH-----Just simply answer the question!!

N_Jay

I read your analogy as "Plutoe read it from MB, Plutoe know all!"

efzauner

Plutoe is just upset cuz he was demoted from planet status...Now hangs around Star System buzzing other bodies.

Schnellfahrer

Per Plutoe:
Read your owners manual before trying to do what you might think is simple maintenance

Schnellfahrer

Thanks for your lecture Plutoe. You sound like a grade school teacher I had a few centuries ago. She had that same condescending tone. And yes, I do read the manual religiously.
My new air filters are in and my knuckles are slightly chafed. Mileage is the same as before plm 36 mpg and the old air filters were not all that dirty to my great surprise. I'm not going to worry about the fuel filter for a while especially since I heard through the grapevine that MB now recommends changing the F/F every 40K instead of 20K. I haven't heard that confirmed though and I don't want to start a rumor so you have to check this for yourself.

kajtek1

Just to add more knowledge to topic - looks like the engine has no air sensor.
The filters on pictures were taken from my new purchase. Car was driven in Tennessee, with more bugs, but I have feeling that at 160,000 miles, those are still factory filters (thanks to 100% dealer service in well stamped book).
I drive diesels with air minders, that tell me when to change filters and even on those that I kept for 100,000 miles the filters were still clean.
Bottom line, the filters below add 2 seconds to 0-60 acceleration time, yet mpg seems the same and NO LIGHT, NO ERROR.
But think about it >>> clog filters = less acceleration= less fuel consumption.