M1 mix 0W-40/15W-50, 12 mo/20k mi, 1990 Saab 900
- Thread starter Eiron
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Okay, here are a couple of shots of how my K&N air filter looked after 90,000 miles without a cleaning.
C900 K&N after 90,000 miles, pic #1
C900 K&N after 90,000 miles, pic#2
As you can tell, I rotated the filter about 1/4 turn every 10k miles or so just to even out the dirt distribution. If I didn't, then there'd be a huge wad of debris right in one spot. I originally thought it was better to do this, but then thought it might be better to keep the "dirt strike" in one spot to minimize migration thru the cotton gauze. So I didn't turn it this last OCI (or was it last two OCIs?), & I think that might've actually contributed to the higher-than-normal Si reading.
You'll notice that the lower half of the filter still looks clean. When I first got it I used to flip it over as well as rotating it. I think I might start doing that again, just to get a clean patch of filter every 10k mi for the next 100,000 miles.
C900 K&N after 90,000 miles, pic #1
C900 K&N after 90,000 miles, pic#2
As you can tell, I rotated the filter about 1/4 turn every 10k miles or so just to even out the dirt distribution. If I didn't, then there'd be a huge wad of debris right in one spot. I originally thought it was better to do this, but then thought it might be better to keep the "dirt strike" in one spot to minimize migration thru the cotton gauze. So I didn't turn it this last OCI (or was it last two OCIs?), & I think that might've actually contributed to the higher-than-normal Si reading.
You'll notice that the lower half of the filter still looks clean. When I first got it I used to flip it over as well as rotating it. I think I might start doing that again, just to get a clean patch of filter every 10k mi for the next 100,000 miles.
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