TLDR version: so BMW only sells the thermostat housing as part of the combined unit of thermostat, housing, alternator bracket, and water pump/coolant pump. BMW part number for my F56S is 11518601366. I want to know what folks' experiences are who have opted to replace (or try to replace) one of these components separately from the rest.

Here's why, on to the less-TLDR version.

I decided to replace the water pump with one of higher quality (metal impeller). I didn't think even once about the direction to remove the alternator bracket. That's because I didn't realize two things:

(1) coolant goes *through* the alternator bracket. So you don't just have the pump gasket to worry about (comes new on a new pump, no biggie there). You have the gasket between the alternator bracket and the engine block to worry about.

(2) you guessed it, BMW doesn't sell a gasket for that. The instruction BMW gives is to, "if the gasket [on the alternator bracket] is damaged," remove the gasket and replace it with a bead of Loctite 5970.

Now, Loctite 5970, like any other sealant, has a cure time. Here's what I found on that.

• The TDS (Technical Data Sheet) for Loctite 5970 shows a full cure time of 21 *days.*
• Dry-to-touch is referenced as 25 minutes by multiple parties. That said, dry-to-touch time is not full cure time. And this is a high temp environment with fluids (coolant), yadda yadda etc.
• In a YouTube from a mechanic shop (go to the 21 minute mark to hear this detail, video link at end of this post), a guy who had BMW tech contacts did some calling around while messing with this scenario. He was told by his BMW tech associates -- multiple and at least one at the master level if I recall correctly -- to let the bead cure for no less than 24 hours.
• None of this exactly inspires me to think "hey, you can have a shop pull this apart, put it back together, drive away and no worries about leaks." At minimum you:
  • do the physical part install with associated fun-with-Loctite-seal,
  • let the car sit with its engine still non-runnable (like where, in the shop's lift?) and cure for 24 hours,
  • and THEN you put coolant in and start everything up.

If your head is spinning about having to Loctite-seal the alternator bracket in order to upgrade your water pump, you're following along quite well.

Enter the whole business of "what's the alternative?" Well, the alternative is to buy a new alternator bracket that has a new bracket-to-engine-block gasket on it. Which you can't. Well, you can, but the bracket will come with a new BMW water pump and a new BMW thermostat and a new BMW thermostat housing attached to said bracket -- non-optionally and priced accordingly.

(I haven't even gotten to the scenario where you have to replace your thermostat housing. Remove that alternator bracket from the engine and you've got the same problem.)

For anyone wondering how mine turned out -- well, the work is still in progress, and I'm having a shop install the upgraded water pump. I stood with them in person, took one look at that alternator bracket coolant gasket, pictured removing it and replacing it with Loctite 5970, and did a whole lot of Loctite contemplation. And then I went "nah, half the reason I'm in here is that coolant handling on the MINI cooks the plastic and the rubber and the gaskets and anything nonmetal and and and. Not playing with Loctite for this." So I caved, sourced and procured a new BMW alternator bracket that had a new gasket. And non-optionally, also had a new BMW water pump (which we were going to detach immediately post-purchase) and new BMW thermostat and housing already attached.

Since I trust BMW plastic as far as I can throw it where coolant temps are concerned (did I mention that?), I was fine with "while you are here" giving the car the new thermostat-stuff that was already attached to the new bracket. At least that made some sense and I could justify a chunk of the unexpected additional spending.

All that said, when this is all done I will have the upgraded water pump on that bracket, and I will have the following spare parts:

• Old BMW "combo part assembly" consisting of:
  • alternator bracket
  • water pump (removable from old bracket)
  • thermostat/thermostat housing (removable from old bracket)
• Brand spanking new BMW water pump (removed from new bracket)

So I'm wondering -- if you have replaced/upgraded your water pump, or replaced your thermostat/thermostat housing, how did you navigate this, and how did it turn out over time? I don't think I'd change my decision here, but I know that I'm paranoid about the BMW plastic + coolant combo (from my experiences with my R56).

Above-referenced YouTube link:

 

Thank you for this detailed post. About how much was that part and where did you get it?

 

I got part 11518601366 for $237 plus tax, local pickup (so no shipping/handling) from the folks at atlantabmwparts.com (which is an actual BMW dealer).

The lowest price I've seen online is $187 at genuinebmwminiparts.com, which also appears to me to be a BMW dealer site. But the thing with any online dealer part sites is shipping & handling can raise your actual acquisition cost up to effectively match what what you'll pay to "free shipping/handling" shops like ECS Tuning or FCP Euro.

My strategy on parts is largely to grab something locally if my need is time sensitive and/or there is not a big price differential, or if I want to visually inspect the part in real time (vs after it arrives in a box kicked around by Fedex for 5 days or... you get the idea). But local isn't an option for everyone, and there are also ands/buts of all kinds so... yino.

 

We also have Lifetime Replacement on Genuine MINI and we run sales on Genuine MINI parts. All MINI dealers just do 2 year warranties, we beat that by a far amount. https://www.ecstuning.com/LifetimeReplacement/

If you are time sensitive (car down and need fixed same day) and close to a dealer it makes sense.

Right now we have a sale.

https://www.ecstuning.com/b-genuine-mini-parts/


Hepu has a metal impellar type now. https://www.ecstuning.com/b-hepu-par...pump/p436~hpu/

Wahler has that top part now also. https://www.ecstuning.com/b-wahler-p...518601366~wah/

 

@cargusjoh , a quick update for you. Haynes has a video showing replacement of the water pump, without removing the alternator bracket, on YouTube for the 3-cylinder F56 engine (base Cooper). From that video I think a direct swap of the water pump without getting into all the alternator bracket crazy is viable. There is still the business of the seal, but if you are fitting a new water pump, that new pump is going to come with a new anaerobic seal bonded to the new pump. Guidance would still be to let the thing sit post-physical-install for 24 hours before putting any coolant in there, but you get the idea.

On my earlier concern about the 24 hour vs 21 day business, I think I have to look to the real-world fact that these pumps get replaced on a regular basis and there aren't BMWs stalled with blown water pump seals littering the roadsides. My takeaway is that if one observes the 24-hour "sit period" they will be in as good shape as anyone is ever going to get, even as the seal continues to cure over the next 20-odd days.

The only caveat: on a 4-cylinder engine I don't know how viable removal and replacement of the pump alone is or is not. Clearances are crazy tight when the F56 engine bay has a 4-cylinder in there -- the gap between the front of the pulleys and the wall of the engine bay is narrower than the width of the serpentine belt itself. I would love to see a YouTube of someone getting the water pump off thoughtfully on an F56 with a 4-banger, but until I do I think that scenario has to be regarded with some caution (and still with at least the legwork in the Haynes YouTube for the 2014-2018 Mini One with the 3-banger).

Finally, no complaints with the new water pump in place. I think the work was worth it between getting the replacement pump in (Meyle HD, metal impeller) and what it taught me about how the engine is put together.

 

Thanks for this detailed information!! This is very good write up!

 

Yeah, pain in tha *** this job, and it is mainly the sealant part of it on the Alternator Bracket. The gun for the sealant I was only able to track down from China. When I got the Coolant pump this as mentioned came with a seal. I replaced the gasket on the main bracket and it leaked. I did the job again and every thing looked good. Now in the video, they mechanic says the bolts for the bracket are steel and can be used again. Not so, after doing the job a third time, after several month of no challenges, when I went back in, I noticed that the bolts were loose. When I enquired at the dealership, I was told that these bolts are actually stretch bolts. I bought the stretch bolts for the 3rd rebuild and it was then I found out that if you buy the bracket, you get the thermostat housing and coolant pump!!!! Tipical BMW. In the UK the Pump was £165, the Braclet with the pump and Thermo is £265! If I had know this when I purchased the pump first time around, it would have been a no brainer... Oh well... After putting everything back the third time I have an issue with the Thermostat so need to get in there again... I'm just going to buy the entire lot. this time around and sell the Coolant Pump from my first purchase if I can.

 

Too bad you're in the UK, I have a spare pump (new) and bracket + thermostat (old) that I'm getting ready to put on eBay because when I ran into all this the approach we took was "eff it replace it all otherwise we may be doing this all over again"

Good and important note you put there re the bolts. I didn't specifically know the ones in this discussion were stretch bolts, but I've learned two things about this MINI:

(1) Replace every O-ring and gasket you expose, especially if it is sealing against fluid or is air-passage critical (and double-especially if your B series engine and its seals are maybe 6+ years old). BMW pretty much has "renew gasket" and "renew o-ring" shotgunned through the per-repair details of many, many things in TIS. And fluid-contact BMW seals tend to shrink and, in the worst case, separate.

(2) Replace any bolt you remove, unless it's a no-brainer that it should be ok or isn't in a spot requiring "disassembly of things" or is a small bolt. Again, it's too easy to encounter and overlook "renew fastener" guidance in TIS. Not as common as the gasket/seal flags, but definitely common, especially with large bolts and mission-critical bolts. And stretch bolts are more common than folks think.

Glad you posted your experience up!

 

Hello All,

The video above shows a lot but my concern is losing AC refrigerant when unbolting the compressor lines. I bought the full water pump bracket assembly, removed the alternator only to realize
the AC compressor has to be removed to install. Unless I am missing something, doesn't the AC system need to be evacuated before disconnecting? Someone in the Youtube comments mentions doing the procedure without disconnecting the compressor lines. Is this really possible?

 

In the first 90 seconds of the video the guy says he evacuated the refrigerant from the system. So in terms of what the video shows him doing, it all presumes you have to deal with that.

Doing the procedure without disconnecting the compressor lines? No idea. I had a shop do the work. There was no charge on the invoice for refrigerant but that doesn't necessarily mean they didn't deal with all that.

I'll leave it to others to chime in in a more informed way...