Do any of these need replacing?

Status
Not open for further replies.
Joined
Sep 1, 2013
Messages
123
Location
ny
The air filter is fine. It doesn't look like it is even ready for cleaning. When you do clean in in another 20,000 miles use the cleaning and re-oiling kit available from K&N.

The O2 sensor looks fine but I don't think you can go by looks. Most manufacturers have a replacement interval based on mileage or you can measure the output with a VOM on a running car.
 
Last edited:
I am not a fan of K&N. I would replace it with a high quality media filter. Your engine will ingest less silicon.

As for the O2, if its an upstream, then roughly ever 100K replacement. If downstream, wait for a code.

If you do replace the O2, either get an OEM or the same company that made the OEM,
 
Last edited:
thanks guys, i didnt even know the k7n was replacable, i thought all air filters were disposable. looks like my car came with a real nice air filter from a few google searches.

as for the o2 sensor, downstream means after the cat, upstream means before, right?

thanks!
 
How many miles on the O2? There are two schools of though on O2 sensors. Some say change it when it throws a CEL others change them as a maintenance item.
I change them out at 100-125K, they do get lazy and are probably not performing optimally at about that mileage.

Filter looks fine if you like K&N.
 
If the OP is happy with a K&N why comment about changing it?

I expect if you replaced it with a piece of wood it would stop even more silicon.

Air filtration is not an exact science.

There is always a compromise between the best possible filtration and flow being reduced so that performance is affected

I will post up pictures of the air filter in my XJL which would appear to have been the factory fitted one, 90k round London in two years!

It would certainly have been filtering well as not much would hsve been getting through.

But it did 27mpg for the first 1000 miles i did and over the last 1200 it has done 37mpg, i did do more out of town usage but not enough to explain that difference.

The DPF light has also not come on since and the vehicle is much happier driving round town.

If the OP is happy then it is all good in my book.

I certainly would be happy to leave that filter another 10k before rechecking and even considering a clean and reoil.
 
Originally Posted By: llmercll
thanks guys, i didnt even know the k7n was replacable, i thought all air filters were disposable. looks like my car came with a real nice air filter from a few google searches.

as for the o2 sensor, downstream means after the cat, upstream means before, right?

thanks!


K&N's claim to fame is that it does not restrict the flow of air and you can clean and re-oil it. In practice I do not believe a clean air filter restricts air much more than a K&N. But people with UOA who use a K&N usually see more silicon in the oil (from the air). There is also some concern that people over-oil the filters after cleaning and it messes up the MAF sensor.
 
Originally Posted By: Donald
I am not a fan of K&N. I would replace it with a high quality media filter. Your engine will ingest less silicon.

As for the O2, if its an upstream, then roughly ever 100K replacement. If downstream, wait for a code.

If you do replace the O2, either get an OEM or the same company that made the OEM,
x2
 
A fellow I know has a 535i, the E28 version, with 500K miles on it. He taps the paper element on his shoe every so often. Air filter and fuel filter change intervals are very much dependent on conditions.
 
I don't consider them a maintenance item. A CEL or bad gas mileage is the only time I change them. On some vehicles an 02 can cost $100 or more.
OP...don't forget some anti-seize on it before you put it back on.
 
Status
Not open for further replies.
Back
Top