Aluminum Upgrade 11118629123 and 11531439134 for BMW 40i vehicles with the first generation B58 engine. For just a small amount more than the original price, you can ensure you'll never have to replace this part again.

As these engines age, the plastic degradation accelerates. The factory piece is made out of plastic and has a cap on it, therefore having multiple places for leaks to develop (plastic fitting itself, o-ring for the fitting, cap itself, and o-ring for the cap).

Our product eliminates four failure points by converting it into a one-piece design with dual O-rings.

The fitting isn't used for the cooling system in factory form for cars that don't have remote radiators. Cars with remote radiators are usually packaged with M Sports package (337) and M Sport brakes (2NH). It also appears to depend on if your vehicle was built before or after 03/2016. Vehicles before weren't capped but vehicles after were. To confirm this part is right for you, simply pop your hood and look at the fitting. If it is capped off, it will work!

Our product is cast from aluminum, ensuring extremely long-term reliability. Lubricate the O-rings before install to ensure smooth fitment.

Installation instructions:
1. Remove the airbox and electric fan
2. Cover or remove the belt to prevent coolant spilling on it
3. Remove the E8 torx bolt holding the factory cooling piece.
4. Carefully remove the factory cooling piece. It will disintegrate as you pull it out. Use a pick to carefully extract any leftover pieces.
5. *Very important* Feel the bore that the piece sits in with your finger. There will most likely be a lip built up from corrosion. Using 120 grit sandpaper, go in a circular motion a few times until it is smooth. If this step is skipped, the upgraded part will not fit and you will damage the o-rings.
6. Lubricate the o-rings and align the part with the factory bolt hole. Thread in the bolt by hand and then tighten it a few turns. You can use the bolt to pull the upgraded part into the hole little by little. Be mindful that it should not take much force to turn the bolt. If it does, loosen the bolt a few turns and then tap in the upgraded part using a hammer. If something doesn't feel right, take a step back and repeat. Using too much force with the bolt can result in the bolt breaking inside the block (as the bolt is aluminum) and/or you can strip the threads in the block (as the block is aluminum).
7. Refill and bleed coolant following the factory manual procedure.

Fits these models (40i and 40iX):

1' F20 LCI   (09/2015 — 06/2019)

1' F21 LCI   (09/2015 — 06/2019)

2' F22   (09/2015 — 06/2017)

2' F22 LCI   (09/2016 — 12/2019)

2' F23   (09/2015 — 06/2017)

2' F23 LCI   (10/2016 — 12/2019)

3' F30 LCI   (10/2014 — 10/2018)

3' F31 LCI   (10/2014 — 06/2019)

3' F34 GT LCI   (09/2015 — 12/2019)

4' F32   (04/2015 — 02/2017)

4' F32 LCI   (05/2016 — 12/2019)

4' F33   (03/2015 — 02/2017)

4' F33 LCI   (05/2016 — 12/2019)

4' F36 Gran Coupé   (03/2015 — 02/2017)

4' F36 Gran Coupé LCI   (05/2016 — 12/2019)

5' G30   (10/2015 — 06/2019)

5' G31   (03/2016 — 06/2019)

6' G32 GT   (09/2016 — 06/2019)

7' G11   (10/2014 — 01/2019)

7' G12   (10/2014 — 02/2019)

X3 G01   (10/2016 — 07/2019)

X4 G02   (03/2017 — 07/2019)

Pair this product with our Connecting Pipe O-Ring Aluminum Upgrade 11118619408 for an ultimate upgrade in reliability.