Question: 1986 300SDL 196,000miles. K&H filters. Can anyone tell me why not install one? All I have seenin the posting is do not do it. Lets put aside costs of filter, filter box, Oil from filter and other such items. Give me some GOOD sound mechanical reasons not to do.
Thank you,
Ron Ragno

Ok do a few 0-60 runs with a stock dirty filter and a new stock filter. Then slap on the K&N I bet the times will not change a bit. The turbo will be louder though. Also to flow more air the also let in more dirt, so you will be sucking more dirt into your engine. So will gain nothing and get a little more dirt sucked in with a little more noise. Don't waste your money.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

I fully agree with the previous post.
All you'll get is increased intake noise, and some perceive this as being more power.
More dirt in the engine (less filtering properties with the K&N) is an assured result.
A few cases of beer will do you more good for the same price.

Turbodiesel engines run with an excess of air already. I.e. the stock intake and exhaust systems run more air through the engine than it can use---power is determined solely by the amount of fuel injected. It's not like a gas car where you can open up the intake, slap on a less restrictive exhaust, and thereby gain a few horsepower while keeping the air/fuel mixture constant. From a gas engine point of view, diesels already run lean---so more air does nothing.

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AlexTheSeal: hack mechanic, inadvertent drifting champ, builder of infernal devices, professional epistemologist

'87 300D Turbo, roadtrip mileage champ (for sale!)
'92 Isuzu Trooper, mudder extraordinaire (for sale!)
'82 Honda Silverwing, cockroach of motorcycles
And various boring daily drivers...

And if you had read the posts regarding why not to do it, allowing more dirt in the intake contaminates the hot air film in the mass air sensor, thus shortening its life. Don't know if yours was so equipped or not...

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car

At idle on my '83 TD, I can feel the air being drawn in at the opening for the air intake. Diesel suck in alot of air as is. As mentioned getting more air isn't the issue, it's the fuel. Correct me if I am wrong, but your car has the same 603 engine that is in my wife's '87 TD. If that is the case, you have a mechanically injected engine. Unless you want to take apart the pump and mess with it's calibration, you're not going to get any increase in performance. My wife's car hauls ***. I don't see any reason to mess with it.

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1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member

I just like them because they seem to be more environmentaly friendly. The less I put in the trash the better I feel.

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2014 C250 21,XXX my new DD ** 2013 GLK 350 18,000 Wife's new DD**

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They are just expensive junk. They do as much filteing as no filter at all. Save yourself the money and just remove your filter all together.

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