Retrofitting OEM M3 Dipstick

[karbonkid]

With the recent interest in this modification, I thought I'd share some pics and give a quick insight as to what exactly is involved.

Firstly, removing the Airbox is needed. Removing only the 'Unfiltered Air Housing' should be adequate, giving you enough room.
I removed the entire Airbox (Collector & Unfiltered Housing) as I had other things to perform.

Airbox removed.



Once Airbox is removed you can locate the OEM CSL dipstick.








Remove CSL dipstick. Just 1x small nut to release the dipstick guide tube.



CSL - Left / M3 - Right
(Note - CSL guide tube has bracket welded to it but M3 one comes separate).





Next comes the hardest part - getting the M3 guide tube to fit into the sump and bending the tube to shape avoiding all components on the way before getting the top to fit into its new location where it will be fixed to secure the tube, preventing it from any movement.

The height of the dipstick is crucial so it will not come in contact with the bonnet when closed and when trying to bend the dipstick around the components the height will adjust as a result so it's a bit of a trial and error to get it just right.

I purchased a used one cheaper to get the shape correct before venturing to buy a brand new one to duplicate.

The art is making the bends as smooth as possible without creating too harsh a bend as the dipstick will struggle to make its way around it. The tip is the part that will have difficulty passing through as it is 58mm in length.

If you are thinking of using a used dipstick and tube just check the dipstick tip is in good condition as it is only plastic and they do break up and they could end up in your sump.

I purchased a used dipstick and guide tube which came from a 60k' ish E46 M3 and although it was described as excellent condition I was soon to check its condition of the tip when it arrived and found a very fine hairline crack down it.
Whilst using it to get the shape, I checked the tip again and noticed it was starting to get worse as the dipstick at times was tight inside the tube before getting it just right.

Pics show crack forming larger before it actually broke up when gently bending in my hands. By this time I had finished with it anyway.





The tube is 15mm in diameter and although a pipe bender may be of some use I don't think its necessarily needed, I didn't use one. You will have to have a 15mm guide with the bender and most benders will struggle to bend anything but copper piping. You can fill the pipe with tightly packed sand to help prevent any kinks from forming or by using pipe bending springs. However, you can actually bend it by hand if your careful enough. I did heat some of the bends up a little to help.

If you do manage to get a small kink in the tube, a good tip is to fill the tube with water, cover both ends and put it in the freezer. Water expands around 9% when frozen and is great for pushing out dents or kinks. You may have to repeat a few times for it to be effective but use at your own risk.



New Guide Tube & Dipstick

M3 Guide tube - 11437832140 - £58.19
M3 Dipstick - 11437831140 - £17.21
Bracket - 11437840407 - £1.55


The CSL Dipstick will have the O-Ring & Washer for the M3 one to fit but you could always replace it with new ones.

Washer - 11437838127 - £4.40
O-Ring - 11431707164 - £3.16






Pics below show where I decided the guide tube to be located.
I decided for it to go under the 2 large rubber hoses shown below - to prevent any compression on them to if it was positioned over the top. I then ran it up the side of the wire harnesses in the black casing. I had to remove the black casing to enable me to attach the tube to the body and position it into the sump, then reassemble it back on once the tube was attached to the body.

In order for the guide tube to go under the 2 large hoses I filled down one of the tabs to prevent any wear on the hoses should any movement occur.









I didn't want to make a hole in the bodywork to fix and secure the top part of the guide tube which is the only way I have seen people do it, so I made the decision of attaching it to the plastic cover so it can be reversed by buying a new plastic piece should it need to be. This was the reason why I took the guide tube the way I did in order to allow me to have the end of the tube finish in the area where it can be bolted to the plastic piece.

Below shows it fixed to the plastic.












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