K&N Filters issue

[fatmansv8]

Hi all. Just need to know asap before shelling out on OE filters how bad is the problem of fitting K&N air filters (which I have as part of a service ) to a un- mapped ( alpha N) E39 M5. Do I need to put OE filters back in asap or what!
thanks from confused FatmansV8.

[DVandrews]

The problem with any after market filter that requires oiling is that the oil will be drawn through the inlet in sufficient volume to corrupt the surface of the Mass airflow meter, these are just after the filter. Once they are corrupted the engine will run badly, cleaning them is not a trivial undertaking and they are expensive to replace.

Dave

[fatmansv8]

Gosh darn it. Cost me about £60 those K&N's how long does it take to contaminate iv only done 16 miles since the service. I cannot afford a alpha N remap at the moment. Thanks for the asap reply much appreciated
thanks FatmansV8

[abarber]

I've had no problems in several years with an E90 330i running a K&N element.

[fatmansv8]

Hmm curiouser and curiouser the plot thickens. Thanks abarber

[ecain63]

Arent the OE ones better anyway?

[mmm-five]

If the OP has removed the MAF to run Alpha-N, then there is no issue over fouling the MAF.

OE filters are not particularly expensive, and you can buy filters for £10 each (Eurocarparts has a 25% code running again). Some 'performance' filters are available that can be run dry for normal conditions and wet for dusty/off-road conditions.

[fatmansv8]

I'm not sure if OE are better or not I just put K&N as upgrades.
thanks FatmansV8

[fatmansv8]

In what way would OE air filters be better than K&N apart from the oil issue.
I have been quoted £10 each from Halfords for Maan air filters £7 for Halfords own brand. £28 each from Sytner BMW. Anyone interested in a couple of K&N filter lol

[helix402]

K+Ns do not foul air mass meters. I have used them for 20 years without problems. (I know it was air flow meters and carbs 20 years ago).

[stargazer30]

helix402 said:

K+Ns do not foul air mass meters. I have used them for 20 years without problems. (I know it was air flow meters and carbs 20 years ago).

+1 the oil fouling is usually after the user cleans and re-oils the filter and puts too much on. I've used them for 5 years ish no issues. Not on a BMW though.

[fatmansv8]

Man alive I'm no nearer knowing the solution lol. I guess I can change them back to original equipment till I can afford a alpha N re map. Thanks to you all for input guys.
FatmansV8

[fatmansv8]

Hi. Is there anyone using K&N's panel filters on E39 M5 without alpha N tuning. If so are you having any problems. I had K&N's then changed back to original BMW filters
Now I don't know if its in my head but I feel like the car was running better with K&N's. FatmansV8

[Silent1]

The whole k&n thing is bks, read this:
http://www.knfilters.com/MAF/massair.htm
Also if a dealership says it was the k&n that did it, IIRC k&n will happily take them to court/pay you.

[fatmansv8]

Hi Silent1 thanks man iv just read it enough said really. To be fair and honest BMW had nothing to do with this. I rang Evolve and BW repairs both said put originals back in however Evolve did say " only bad if they are over oiled so I panicked and put the originals back in.
thanks FatmansV8

[mmm-five]

Silent1 said:

The whole k&n thing is bks, read this:
http://www.knfilters.com/MAF/massair.htm
Also if a dealership says it was the k&n that did it, IIRC k&n will happily take them to court/pay you.

It's not bks, but it's down to user error in cleaning/oiling.

So the dealer says the MAF sensor was damaged by the K&N (or its over-oiling), you complain to K&N and they help you go to court.

Who do you think will end up picking up the tab when K&N state that the only way it will damage a MAF is if it's over-oiled, BMW say the filter must have been over-oiled to cause the damage, and YOU are the only person to ever oil it?

Hint: it won't be BMW or K&N.

Otherwise, do you think you're capable of proving that you didn't over-oil it 20k miles ago when you cleaned/re-oiled it?

[fatmansv8]

I have not even done 10 miles with them in. I guess by the sounds of it don't over oil them. I have a few miles to go yet before they need re oiling. I only clock up 1500 miles a year in this beast.
FatmansV8

[sumo69]

I ran them for 4 years on my E39 M5 without issue - when they were new I wiped the edges clean of oil residue from the packaging and then left them on paper towel for 24 hours each side so any excess oil would be removed before fitting.

I never had any issues so still have an unused set of spare MAFS in the garage for sale!

David

[fatmansv8]

That's the kind of info I like. Thanks Sumo
FatmansV8