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5 Series Beamer

Diary of a Second Hand 15 year old Beamer (Maintenance - Battery Drain included...,
BMW E39 520i year 2000 Engine 1995cc)
M Series.

Workshop/Diary - K & N Air Filter

 

fig. Boot - Rear Fuse Cluster

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Workshop

Contents Page

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Stainless Steel K & N Air Filter & Mass Air Flow (MAF)

I have alway found the standard factory fitted MAF Filter to be bulky, taking up much space under the bonnet (hood), I remembered I had put one on my e36 to improve its performance and I believed it did. (Note: The factory fit has been designed to allow for performance.) I decided to transfer my K&N  over the the e39. I had the varied sized collars tucked away in a box  they came with the original unit, they were for attaching  around the Filter aperture to attach to the MAf. As the  e36 was slightly smaller  I required the middle sized collar.

These type of filters are known as 'wet filters' as they require a very thin coat of oil, I find a few sprays of WD40 does the trick. This filter requires a plastic or stainless steel hose to be attached to the front centre cone and routed to the external intake where the standard factory  pipe was attached on the inner wing.(not illustrated).

It is difficult to clean inside because of the mesh on either side. It can be washed in a soapy solution and dried with hot air (Hair dryer).
Be careful not the damage the wire inside.

Wire

MASS AIRFLOW FILTER (MAF)

To Air intake

Clip

Collar
Seal

Check: pins, plug and wire lead

Note: On replacing or upgrading the filter and cleaning the MAF, if engine starts to rev between 2.5-3.5K with no top-end revs, the ECU may require setting to Factory default setting. (see page 34)

I have found there is an increase in perfdormance since  fitting this unit and the car can be described as 'perky'.

Filter prices can be between £15 to £65+ - This one was purchased from Halfords (UK) a number of years ago.

fig. source - Standard factory MAF Fitted Air Filter

MAF

fig. Upgrade Stainless Steel Air Filter (Wet-Thin Oil Based)

Wire

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Anchor Point

click

fig.