[F87source]

Introduction (Images below in the steps):
For those of you who do not know what this part is, it is commonly referred to as the “Mickey Mouse” in reference to the two lobes that makes the round shape look like Mickey’s head. This part on the stock engine is a common plastic part (hose is different) shared over numerous bmw engines from the N5X (N55, N54, and NA motors) and N2X engines. This part over time will become brittle and break at the flange due to repetitive heat cycling, this can at the very least cause a coolant leak and leave you on the side of the road. At the very worst this part especially on the N55 can spill slippery coolant on to the serpentine belt causing it to slip and get sucked into the engine past the front crank seal, this can result in the oil pump getting clogged resulting in engine failure, or at the very minimum an expensive repair as you will have to drop the oil pan and valve cover to clean out the belt fragments. A solution to this issue and what I have done on my car is removing the factory plastic flange and replacing it with an aluminum unit – in this case from rein. https://www.fcpeuro.com/products/bmw...09#description In my opinion I believe every bmw owner should focus on the supporting mods and preventative maintenance mods before seeking for more power, this is a common strategy on cars such as Subaru’s where owners are not spoiled by the a car with such an intelligent ecu that is able to adapt to prevent the engine from blowing. Also note I am not sponsored or payed by FCP or Rein to say anything about this product, I paid full price for this item and I wanted to do a review and install guide for those of you who may need it.

Why Rein over other options:
So there many reason why you should choose the Rein coolant hose flange over the alternative options that I will list below, but note installing the Rein coolant flange on a low mileage car will be extremely difficult because the plastic will still be quite malleable so if you are not really patient you can buy the flange and a new hose from ECS (https://www.ecstuning.com/b-ecs-part...it/004503la01/) to save yourself the hassle of removing the plastic flange.

1) The first reason why you should get the Rein unit over anything else is price, this unit is $17 compared to $70 for the ECS unit with a hose replacement, or $30+ for just the flange itself. In my opinion I would rather save those extra few dollars here (on parts that you can go a little bit cheaper on – more on this later) and there and end put that towards other mods.
2) It is raw aluminum, I know there are a lot of anodized parts out there in all different colors like red, black, and blue for instance. But I have seen a lot of these parts in person and no matter where they come from either from ebay, aliexpress, or from large reputable vendors they seem to always be made in China. This means QC is extremely low and the anodized finish is always either chipped or flaking off, after dealing with oil catch cans and charge pipes with terrible anodizing which puts the risk of aluminium anodized fragments getting sucked into the engine I opted to always stick with raw aluminium.
3) O-ring again this is a huge area that is often overlooked when people go to ebay or aliexpress and buy the cheapest possible flange available, they often come with crap o-rings that may not even be designed to hold coolant. This means over time the O-ring can degrade either due to the chemicals in the coolant or the repetitive heat cycling and end up leaking, meaning you essentially have the same problem you are trying to fix. This is another reason why I went with Rein because they are a known name and the flange they are selling has been tried and trued. Rein also makes the engine coolant hose (bmw p/n 11537598234) and flange kit for oem replacements (https://www.fcpeuro.com/products/bmw...in-11537598234) so I think they are plenty capable and reliable to make a good part.
4) Rough edges are another factor not many people think about, the Chinese made aliexpress and ebay parts are more often than not lousy with extremely sharp edges on the finished parts. This can lead to rupturing hoses, and is another reason to go with a quality part.
5) The factory hose is really really good, it is already guaranteed to fit the car, and is made of an extremely high grade multilayer rubber material with fiber reinforcements inside to prevent ballooning or rupturing which is better than replacing it for no reason with a silicone part that might be inferior. This in my opinion is another reason why to stick with the factory hose and just replace the flange.
6) Fitment was a huge reason why I went with this part in conjunction with the factory hose. I know the flange would have been guaranteed to fit as the part is the same on all cars, however I was worried about a hose replacement kit not fitting. If the hose was even a bit off it would have bent the hose leading to a smaller inner diameter or even a kink which would be bad for the coolant flow. Since the factory hose came off of the car and already fit without issue, it was logical to go this route. The reason why I have concerns about fitment is that I know my m2 is different than others, as I bought an oil catch can kit that fit on other m2’s but did not fit on mine. So I know there can be small variations between cars and I wanted to play it safe.
Installation:
Ok before you guys even begin with the install you must be ready to bleed your coolant system and to remove a lot of parts, so I recommend doing this if you are going to install a diverter valve as you will be removing the same amount of stuff to get there.

The skill level of this install is pretty low at 3/10 (it is mostly a patience thing that makes this hard not skill wise), but if you have never worked on a car before this is probably not going to be a place to learn as there are things that can go wrong. You should also be ready with the necessary parts like G48 antifreeze (the bmw blue antifreeze), and distilled water. You should also have access to the bmw technical database which is ISTA, and you should have the basic knowledge to remove parts, drain fluids, and basic improvisation skills if things go wrong.

Step 1: Remove: right strut brace, air intake, turbo inlet (because the hose attaches to the thermostat and the only way to reach the thermostat is by removing the inlet).
Step 2: Remove the front underbody panel that covers the area between the front bumper and stiffening plate, then remove the stiffening plate.
Step 3: Drain the coolant by disconnecting the coolant hose going to the coolant pump.
Step 4: Remove engine cover, then cover the serpentine belt area with newspaper to ensure no coolant spills onto this area.

Quickly we will look at where the coolant hose flange is:
Picture 1:

You can see from this image just to the left of the oil cooler lines a small hose coming out of the head of the block.

Picture 2:

This is a closer up image of the flange and you can see one of the two bolts which are 10 mm in diameter that you will have to remove later. You can also see the cable going into the coolant temperature sensor which you will have to disconnect.

Picture 3:

This is an extremely close up image of the coolant flange and you can now clearly see the two bolts and the coolant temperature sensor connector with a clip on the bottom side that you will need to press in.

Step 5: Disconnect the connector from the coolant temperature sensor by pressing the tab upwards on the coolant temperature sensor connector and pull it outwards towards you.

Step 6: Using an 8 mm socket loosen the worm gear clamp on the bottom of the coolant hose that connects to the thermostat. Then shake it to make sure all of the coolant is drained from the hose and the head.

Step 7: Put some towels below the coolant flange in preparation to remove it. For tools a socket will not fit because the clearance between the flange and the oil lines and cables surrounding it is insanely tight so we will need a 10 mm spanner with a slight angle (if the angle is too aggressive it will hit, so you might need to play around with your spanners) on the box end. I do not recommend a flexible boxend spanner as you will not get any control and it will be hard to apply torque without the spanner possibly moving and damaging something. Use the box end spanner to remove the 2 10 mm bolts. Then you will need to use a non marring pry tool to pry the plastic flange away from the block because it will be really stuck in there. If you properly drained the coolant nothing should spill out.

Step 8: After the coolant hose flange is removed and you can hold the whole hose assembly in your hand you have 2 methods to remove the flange from the factory hose.

1) If your car is higher mileage your hose will have degraded enough that you can easily use a set of channel locks to crush the metal ring on the hose and destroy the plastic flange from the inside this allowing your to pull it out.
2) If your car is lower mileage like mine you will never be able to crush that as the plastic will be too durable. So you will need to do the following, get a hack saw and cut the flange part off right at the gap where the rubber hose ends. Be careful not to cut the hose, you can accomplish this by using a small screwdriver to push the hose back and put the hack saw blade in there and begin to cut. Once the flange is off you will have a small amount still stuck inside the hose held in my the metal ring, this is the crappy part. Remove the hack saw blade and use that to hand cut the flange inside of the hose in half by pushing the blade in and out of the hose. Cut it in 2 parts so you can physically split the plastic bit in half, be careful not to go too deep so you don’t cut the hose. Once it is cut deep enough you can squish the hose with channel locks and the plastic will break free and you can pull it out. Once the plastic is out you can squish the hose and pull the metal ring off.
Step 9: Rinse the hose out with the distilled water that you should have to mix new coolant, this will ensure there is no plastic bits left over.

Step 10: Put the Rein coolant flange into the hose, at this point you may either use the clamp that came with the Rein flange or you can do what I did and buy a worm gear clamp because I hate the style of clamps that come with the Rein flange. But whatever you do, do not tighten the clamp yet as you will still need to make some adjustments.

Step 11: Lubricate the O-ring on the Rein flange and push it back into the block. Then reinstall the two 10 mm bolts with your box end wrench. You will not be able to get a torque wrench into this area so tight is tight, but be careful if you over tighten you will strip the threads on your head and that is going to be a huge problem because you will not be able to easily helicoil these holes without removing a whole bunch of stuff. Note your bolt holes might have dried coolant chunks or even wet coolant in there so it is best to use a Q-tip to clean out the hole. This will prevent cross threading or having the bolts be seized in the future.

Step 12: Reinstall the hose end back onto the thermostat and retighten that clamp according to ISTA specs if you monkey power this you will crack your thermostat so either use a torque wrench or do it by feel. Also make sure the clamp is positioned within the white marks as specified by ISTA.

Step 13: You may now put the clamp onto the Rein flange, if you used a worm gear clamp make sure you tighten it well so coolant does not spill, but again do not over tighten this.

Step 14: Reinstall all the parts you removed, bleed the cooling system and you are done. Congratulations you have bullet proofed another part of you M2.

If you liked my review and install guide please give this post an appreciate, and like always if you have questions or need help with the install post below or PM me.


This DIY is also suitable for M235i, 335i, and 435i owners, so hopefully it helps you guys out as well since I saw zero diys out there and wanted to make sure anyone else that wanted to do this after me could do so.

[F87source]

VisualEcho

Here is the Rein flange install guide that we talked about if you are still interested.

[VisualEcho]

Originally Posted by F87source

VisualEcho

Here is the Rein flange install guide that we talked about if you are still interested.

Dude, this is awesome!

[nothingman]

Thanks for the write-up. I just ordered one and will be installing it alongside the CSF radiator upgrade with my turbo project.

[F87source]

Originally Posted by VisualEcho

Dude, this is awesome!

Haha thanks, I'm glad you like it. I wish I took more photos while doing it, but unfortunately my hands were so slimey while doing this mod I didn't want to touch my phone.

[F87source]

Originally Posted by nothingman

Thanks for the write-up. I just ordered one and will be installing it alongside the CSF radiator upgrade with my turbo project.

No problem! I'm glad you liked it.

Which one did you order, the rein or alternatives? I cant wait to see your turbo upgrade project btw.

[Poochie]

#Bump for a very informative thread, on a common issue with higher-mileage N55s.. 👍🏻

https://www.bimmerpost.com/forums/sh...php?p=27192761

https://www.bimmerpost.com/forums/sh...php?p=27149518

[Poochie]

Originally Posted by PrinceCity

If consern of this oem part breaking...

You can order the OEM plastic part through FCP Euro and get free replacements for life

OR

You can order the aluminum piece from the same place, get free replacements for life, and never end up taking advantage of it.

Game. Set. Match.

Good stuff but the OEM flange comes with a new hose attached, while the aftermarket piece is just the fitting, so you have to reuse the same old hose.

Seems like a no-brainer to replace the hose once you're tasked with that job.

[F87source]

Originally Posted by PrinceCity

If consern of this oem part breaking...

You can order the OEM plastic part through FCP Euro and get free replacements for life

OR

You can order the aluminum piece from the same place, get free replacements for life, and never end up taking advantage of it.

Game. Set. Match.

Unfortunately it's not that simple. When the flange fails due to age it leaks and if it gets on the serpentine belt it will cause it to slip and enter the engine. Then you'll have to pull the oil pan and valve cover to pick out belt fragments, and you'll need to repair the front crank seal - if your engine hasn't blown. These jobs are a huge pain to do and aren't cheap.


So the whole goal is preventative maintenance, not wait until it fails.


But yes with the aluminum part you likely won't get to claim life time warranty, however fcp has a really good price on it and if you read my original post I prefer raw aluminum over anodized.

[F87source]

Originally Posted by Poochie

Good stuff but the OEM flange comes with a new hose attached, while the aftermarket piece is just the fitting, so you have to reuse the same old hose.

Seems like a no-brainer to replace the hose once you're tasked with that job.

The hose is an incredibly durable multilayer rubber or nylon material that is also reinforced from baooning internally with a wire weave. I have never seen this part fail even on extremely high mileage cars, it is on the plastic flange. So no real need to replace this part.


There was a few reasons why I chose to keep the oem hose:

1) it's extremely durable, even compared to after market silicone hoses. This is great so worm gear clamps don't cut or damage the exterior.
2) it has perfect fitment, sometimes after market parts don't fit correctly and I don't want to kink a coolant hose.
3) makes the whole process cheap as I don't have to spend money where it's not needed.


If you don't want to cut the hose like I did ecs sells a silicone hose and flange as a bundle for ~$70, but they'll sell the silicone hose standalone for like ~$38. It's really your choice.

[Poochie]

Originally Posted by F87source

The hose is an incredibly durable multilayer rubber or nylon material that is also reinforced from baooning internally with a wire weave. I have never seen this part fail even on extremely high mileage cars, it is on the plastic flange. So no real need to replace this part.


There was a few reasons why I chose to keep the oem hose:

1) it's extremely durable, even compared to after market silicone hoses. This is great so worm gear clamps don't cut or damage the exterior.
2) it has perfect fitment, sometimes after market parts don't fit correctly and I don't want to kink a coolant hose.
3) makes the whole process cheap as I don't have to spend money where it's not needed.


If you don't want to cut the hose like I did ecs sells a silicone hose and flange as a bundle for ~$70, but they'll sell the silicone hose standalone for like ~$38. It's really your choice.

Thanks for the info, I'm impress that you was able to predict that this is a wearable part and was prone to eventually fail, specifically on the newer N55, before there was really any reported cases..

When you posted this reply, I had already ordered an OEM replacement hose/flange, from a dealer but I plan to also get an aluminum flange piece you suggested, attach it to the original hose I'm removing and keep that as a backup unit.

I don't plan to keep my car that long for me to ever have to deal with this again, more or less, even with the backup OEM hose but won't cost much to have a replacement available, regardless..

It just shows that these cars are not made to last forever over really over 5 years or so, as the plastic components will wear out but at least with threads like these it can lessen the blow, by eliminating the element of surprise of it failing..

[F87source]

Originally Posted by Poochie

Thanks for the info, I'm impress that you was able to predict that this is a wearable part and was prone to eventually fail, specifically on the newer N55, before there was really any reported cases..

When you posted this reply, I had already ordered an OEM replacement hose/flange, from a dealer but I plan to also get an aluminum flange piece you suggested, attach it to the original hose I'm removing and keep that as a backup unit.

I don't plan to keep my car that long for me to ever have to deal with this again, more or less, even with the backup OEM hose but won't cost much to have a replacement available, regardless..

It just shows that these cars are not made to last forever over really over 5 years or so, as the plastic components will wear out but at least with threads like these it can lessen the blow, by eliminating the element of surprise of it failing..

Yeah no problem. I knew this was a failing part for the longest time because bmw has been using this plastic flange since 2006 but with different hoses, I just wanted to wait until warranty was done before I replaced it.

I also knew the coolant expansion tank hose would eventually fail but there is no after market fix so what can you do.


Well I wouldn't say that these cars aren't meant to last for a long time because the critical components like the drivetrain is quite stout. But bmw just has a habit of cheaping out on some parts that should be metal like this flange. They also don't like changing/improving their designs for an extremely long time which is also unfortunate, but I wouldn't fault the car overall.

[Pray for Mojo]

Rockauto has the Rein flange, at least under the 2014 M235i parts. Another option to order from that usually has the cheapest shipping for folks north of the 49th.

[F87source]

Originally Posted by Pray for Mojo

Rockauto has the Rein flange, at least under the 2014 M235i parts. Another option to order from that usually has the cheapest shipping for folks north of the 49th.

Good to know!

I was buying a bunch of stuff from fcp so I got it there as well.

[celsdogg]

great write up, thanks!

In step 12, what is the value for the torque of that clamp?

[F87source]

Originally Posted by celsdogg

great write up, thanks!

In step 12, what is the value for the torque of that clamp?

There's no specified torque because it's not included with the rein flange. So I would use 8 nm like bmws specified torque for the other worm gear clamps. Or hand tight, try not to go too crazy.

[F87source]

I should also mention when using a worm gear clamp the concern with high torque isn't the flange itself because it's metal unlike the plastic flanges on the old coolant flange and the flange on the thermostat. The concern is that you tighten it so much that the worm gear clamp cuts the OE hose, or you break the tracks that the clamp rides on. With a good quality clamp like what bmw uses the edges are rolled so they are not sharp so the risk of cutting a hose is less. I recommend using clamps like that, and it is also the style of clamp I personally used.

[TheHunterHofman]

I made a video about the same process, with the help of F87source , massive thanks to you again.

Video:

Hope that helps/entertain some of you.

[vrooooom]

how much G48 antifreeze do we need to get?

My apologies if that was already there and I'm just too blind to see. Got the mickey flange from Amazon. https://a.co/d/1CVGhjj

I guess we really need to pull that whole hose out bec of that clamp that needs sawing off. I almost wish I knew about this when I did the work on my diverter valve.

[3t3p]

How much shop time to do this? Would it be good to access same time as a HPFP upgrade? Thanks

[TheHaze]

Originally Posted by vrooooom

how much G48 antifreeze do we need to get?

My apologies if that was already there and I'm just too blind to see. Got the mickey flange from Amazon. https://a.co/d/1CVGhjj

I guess we really need to pull that whole hose out bec of that clamp that needs sawing off. I almost wish I knew about this when I did the work on my diverter valve.

My car took just over 1 gallon of 50/50 coolant mixed with distilled water when I did my flush a couple weeks ago. OEM coolant part numbers are 82141467704 (gallon) and 82142209769 (liter).

[F87source]

Originally Posted by 3t3p

How much shop time to do this? Would it be good to access same time as a HPFP upgrade? Thanks

It's not in the same area as the hpfp so it wouldn't make a difference. It should take a shop 30 mins to do this not including a coolant flush. So 30 mins shop time + a coolant flush.