David Gold

good day i have installed the k&n intake filter for my early 2011 sline q5 and i have noticed i am consuming more collant than previously and oil?

anyone else had this issues

q5 dave

i know people say those filters are MAF killers

raj99

Dave, if you are "consuming more coolant", otherwise known as losing coolant, you have bigger issues than your air filter. Since the air filter should not have any impact to your coolant...which you should resolve ASAP.

ZCD2.7T

This only occurs if you also changed to synthetic blinker fluid at the same time as you changed the air filter*...
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*kidding.

There's no connection between air filters and coolant use.

gema1727

Hello David,
Should not make a difference. Mine has been on for about 7 months and (knock on wood), nothing out of the ordinary.

MP4.2+6.0

Unrelated. But yes, if you have an MAF motor, Bosch or Hitachi will appreciate your future MAF business. Long term performance subtract.

Redd

The air filter physically cannot have any effect on fluids consumption. But as others have noted it can ruin an air mass sensor. K&N especially is a concern because many of their filters are oiled, or designed to be re-oiled after cleaning by the user. And that oil forms a film on the air mass sensor, which fouls it, requiring cleaning or replacing.

If you actually speak to K&N, they won't specifically guarantee any increased performance on many cars. A skeptic would note that's because some of their filters have been tested against OEM "performance" filters and the OEM filters were found to be just as effective. At a lower price.

Your mileage may vary.

But if your oil and coolant are both being consumed, it is time to check for larger problems, possibly a failing head gasket. Sooner, rather than later.

Sigq5

I echo Redd's caution on being careful on potential impacts to mass sensor, and share my limited experience below

We've had K&N filters on our past vehicles, and really wanted to use K&N filter on our new cars including our Q5TDI. However, I became skeptical when I saw performance data on how much small particulates they allow to pass through, and could not find reliable data that they improved performance over OEM filters. The clincher for me was testing I saw in it iTube where they showed no performance improvements unless you supercharge or turbocharge engines.

I could not accept the risk of impacting our cars over questionable benefits

Redd

Sigg-
When "the K&N question" came up some years ago in another place, one of the forum members there had access to a manometer, an airflow pressure test gauge. He'd bought a K&N "cone" filter to try improving his engine performance, on a n/a stock engine which had a special designed stock linear airflow induction system, which most of us thought looked terribly odd. He tested the airflow into the engine intake, behind the stock filter and intake setup.
Then he removed the stock setup, installed the K&N freebreathing cone as instructed, and tested it again. Funny thing, the K&N didn't beat the stock in any way. And, that was ignoring whether the K&N was letting in more particulates and grit.
There's some thought that K&N may, sometimes, be a good alternative for folks who have done heavy mods and exceeded the needs of a highly modded engine. That's possible, since a factory system is matched to a stock engine, intake and exhaust alike.
And of course some stock systems weren't well designed, although with each maker concerned about getting higher EPA figures, they have real good incentive to build a good airflow system.
But. Carburetor "improvers" and other "boosters" have been around for along time.(G)