I went to Kragen to replace my air filter, and they didn't have the filter I wanted (regular OEM), so they sold me a K&N filter. A few days later the Check Engine light came on and my car stalled, not starting until I put in a fuel filter in the gas tank. Even then the acceleration was slow. I then tested the engine with the OBDII tester, and it said there was a problem with the oxygen sensor, so I took it in to my mechanic. To my utter horror, he said I need $2,000 worth of work on the engine because of the fact that the air intake was too strong for this type of oiled air filter. Is this a well-known issue? Is K&N aware of this? Is Mercedes aware of this?

It is possible that your MAF could become contaminated which could alter the air/fuel mixture. Improper mixtures have been known to cause expensive damage such as cracked pistons from detonation (lean) and melted cats from unburned fuel (rich). I would never use a K&N in my car...

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

Too much oil on the air mass sensor CAN cause damage to any MAF..

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MERCEDES Benz Master Guild Technician (6 TIMES)
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190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Find another mechanic,.........fast.
He either does not know what he is talking about, or ripping you off.
When people " over-oil " a K&N filter ( after cleaning ), it can cause problems with your mass airflow sensor in the future.
Since you purchased yours brand new, it would NOT have been over-oiled.

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2007 C 230 Sport.

There are lots of write-ups about K&N filters -- some positive and some negative. But even in the negative articles, all indications are that they flow just fine (maybe slightly better than stock). That their weak spot was their ability to filter fine particles... and the fact that the oil has the potential to wreak havock with MAF sensors.

I've never heard/read anything that indicates they flow poorly. In fact, they are used in lots of racing applications in which they're run at WOT for extended periods. If they failed, I'm pretty sure the racing community would drop them like a hot potato.

Your tech's logic sounds a little cloudy. I'd get a second opinion.

Just my 2 cents, arguably worth that.

Jeff Pierce

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Jeff Pierce

Current Vehicles:
'92 Mercedes 190E/2.3 (247K miles/my daily driver)
'93 Volvo 940 Turbo Wagon (263K miles/a family truckster with spunk)
'99 Kawasaki Concours
Gravely 8120
Previous Vehicles:
'85 Jeep CJ-7 w/ Fisher plow (226K miles)'93 Volvo 940 Turbo Wagon
'53 Willys-Overland Pickup
'85 Honda 750F Interceptor
'93 Nissan Quest
'89 Toyota Camry Wagon
'89 Dodge Raider
'81 Honda CB 750F Super Sport
'88 Toyota Celica
'95 Toyota Tacoma
'74 Honda CB 550F

Before you spend a ton of money, spend a little, and buy a can of Air mass meter cleaner, and give it a thorough spraying. (remove the protective grid - watch the snap ring, so you don't loose it).
Check our fellow member JimF's website http://pages.prodigy.net/jforgione/MB_MAF.html This ought to answer a few questions.
Good Luck!

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It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D

That mechanic is a dumbass. Your engine may very well need a total overhaul, but your air filter has nothing to do with it.

PS - I've tested the K&N vs the paper filter and found that a new paper filter breathes better than a new K&N, but a dirty K&N breathes better than a dirty paper filter.

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- Brian


1989 500SEL Euro
1966 250SE Cabriolet
1958 BMW Isetta 600

i too, was going to recommend buying some Mass Air Flow cleaner. I just checked it out at the local parts place. if i remember right it is made by cfc or cmf or something like that (they make a wide range of cleaning products like brake cleaners and carb cleaners etc) for right at $6 and change.

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1994 C280
2009 VW Tiguan
1993 Toyota X-tra Cab SE-5


1973 220D ... Gone, but not forgotten
1991 Alfa Romeo 164L Gone, wife MADE me forget it

2006 Hyundai Tucson... just straight out FORGOTTEN!

Depending on the model you have, which you didn't post you may have two MAF's. Its possible both could fail at once, but labor to change them should be almost zip. They take like 10 minutes to change. I can see $800, maybe but thats high.

Its pretty commen knowledge that an over oiled K&N can blow MAF's. Your post is one of many.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Run don't walk away from this mechanic. If its an MB dealer run faster.

K&N filters have wreaked havoc on many engines. They are fine for racing, as the engine gets tossed after a couple races anyway. In road use they cause more trouble than they are worth. They do NOT adequately filter the air unless oiled enough to ruin the air flow sensor (and they only sometimes respond to cleaning). The dirt that goes through once the oil blows off will eat the rings, cylinder walls, and valve seats, although this won't be instantaneous. Under no circumstances are they as good as the factory air filter, ever.

The "cold air intake" kits are worse, resulting in significantly LESS airflow at partial throttle and up.

Unless you burned the valves or something, all you did was toast the mass air flow sensor. The O2 sensor fault is because the computer cannot control the fuel mixture to get the correct response from the sensor.

$2000 ain't a big amount -- if you were talking valves or pistons it would be at least twice that anyway. I'm guessing R&R intake, clean up, new fuel filter, new airflow sensor ($800 if it's a dime) and possibly a new O2 sensor (or two, or four). May need new plugs, too if they got burned by the lean mixture.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!