[rlesko]

I still can't discern how the auxiliary pump plumbs into the cooling circuit. But its definitely there, the technical document doesn't touch on it at all. But at least we can conclude there is no different thermostat for it (I think...).

https://www.realoem.com/bmw/enUS/sho...12#11517583965

[visionaut]

On the Realoem diagram for my own ‘16 435iX THP with both hot & cold climate, and the many other US/Eur 435 varieties that I reviewed, the aux pump is greyed out. Maybe it’s a 3-series only thing? I didn’t go very deep on the 335 varieties.. not realizing they’d be very different.

[Boostedphil698]

I wish there was just a good diagram of all the coolant plumbing.

[visionaut]

Originally Posted by thejeremyman9

…nothing belt driven.

Correct. And I’ve replaced my serpentine belt too, and should know better. But RealOEM showed this: “11282457049 — Set, belts for water pump, alternator” when searching on Water Pump. Duh, no. It’s just Alternator belt obvs…

[F32Fleet]

For my M-Sport 2015 435i

https://www.realoem.com/bmw/enUS/sho...diagId=11_5112


Note two water pumps.

The THP wasn't an option when I ordered in 2014.

[visionaut]

Okay, so being curious, I checked on the auxiliary pump again, and it’s not a 3er vs. 4er thing. BTW, it simply traces to “M Sport”, not “M Brakes” like the aux radiator itself..

Believe it or not, in RealOEM the aux pump shows up for an F32 435i and 435iX, and an F36 435i, but not for my car, an F36 435iX. WTF? Reality or RealOEM glitch? I suspect the latter…

[Polo08816]

Originally Posted by rlesko

I still can't discern how the auxiliary pump plumbs into the cooling circuit. But its definitely there, the technical document doesn't touch on it at all. But at least we can conclude there is no different thermostat for it (I think...).

https://www.realoem.com/bmw/enUS/sho...12#11517583965

Hah, so every time I reply, I feel like I have to preface it with ... to be best of my recollection since it's been a while before I got into the coolant plumbing system...

But I think this diagram provides some more (but very limited) insight into the auxiliary coolant pump.

https://www.realoem.com/bmw/enUS/sho...diagId=17_0676

It may have some direct association to that engine oil heat exchanger (Item #26).

I will say that this all becomes much more clear once you remove the coolant expansion tank and look at how that part of the system is plumbed. The rest of the "mystery" were just 2 more general areas:

1. Near the liquid to liquid transmission oil exhcanger
2. Near connections to the front coolant radiator (for the ZF 8HP)

Once you recon these 3 areas (to include underneath the coolant expansion tank), it all makes more sense.

[rlesko]

Just in case anyone is wondering what visionaut clipped in a screenshot earlier, its from this thread - https://f30.bimmerpost.com/forums/sh...65&postcount=7 (I was curious so I went digging)

So, I think with our collective minds we can solve this, along with some simple inferences.

For sake of brevity I won't list screws, bolts, or small items like that at this time. I'm assuming starting with an F3X car with N55 and auxiliary oil cooler.

First of all, it seems the primary radiator is different. There is a special radiator with different plumbing locations as well as space for the transmission radiator to wrap around. The left radiator mount appears to be the same for all variants (can reuse)

Radiator - 17118672103 (provides space for transmission cooler)
Radiator Mount - 17117600538 (right side only)

Moving along to the auxiliary radiator, you would obviously need said radiator and bracket.

Aux Radiator - 17117628057
Frame - 17219452275

It appears a big difference is how the auxiliary oil cooler in the passenger wheel well is connected between M-Sport and Non variants. Non M-Sport has 17227639450 which is a single part for inlet/outlet pipes which goes directly into the oil cooler from the thermostat on the oil filter housing. On M Sport it seems there are three disparate inlet/outlet pipes and somehow an additional heat exchanger are connected between. From real OEM it looks like 17227639643 runs from the oil thermostat to the auxiliary oil cooler. And then it looks like some combination of two pipes 17227626331 & 17227639644 plus the auxiliary heat exchanger 17217628058 must form the loop back.

The auxiliary water pump - 11517583965 is plumbed into this heat exchanger, and both are supported by this bracket - 17217628760 .

Now, the fun part. Lets start working our way through the hoses beginning at the primary radiator.

Coolant hose from primary to auxiliary radiator - 17127627101
Coolant return hose from auxiliary radiator to auxiliary water pump? - 17127627102

Coolant hose from auxiliary water pump to additional oil heat exchanger - 17127627103
Coolant Hose from additional heat exchanger back to primary radiator 17127627104

Now, in terms of what I can envision / infer from realOEM gets a bit fuzzy.

Transmission Radiator - 17117600535

is present, but I can't really fathom how its connected. I think it connects to the heat exchanger that is mounted directly on the radiator fan housing, but I'd have to be physically looking up at my car to imagine how the rest is connected. I know hoses 17127627105 and 17127627106 are involved but thats literally just grabbing part numbers from realOEM And pasting them here.

I reviewed the N55 technical training PDF and the cooling circuit there seems to not mirror our cars. I wonder if its for E series N55? You can there are quite a few different subtleties.

I haven't been able to determine which wiring harness needs to be changed yet to power and control the auxiliary water pump, but my guess is that it simply splits the primary water harness power / control - which means if you were crazy enough you could possibly tap into the wiring harness directly instead of replacing the whole thing. That is a total speculation though.

I was googling some pictures by part number and this came up - thanks to whoever decided to sell this assembly on eBay!



It really helped be 100% sure how some things are connected without inspecting an actual car.

[Boostedphil698]

Originally Posted by rlesko

Just in case anyone is wondering what visionaut clipped in a screenshot earlier, its from this thread - https://f30.bimmerpost.com/forums/sh...65&postcount=7 (I was curious so I went digging)

So, I think with our collective minds we can solve this, along with some simple inferences.

For sake of brevity I won't list screws, bolts, or small items like that at this time. I'm assuming starting with an F3X car with N55 and auxiliary oil cooler.

First of all, it seems the primary radiator is different. There is a special radiator with different plumbing locations as well as space for the transmission radiator to wrap around. The left radiator mount appears to be the same for all variants (can reuse)

Radiator - 17118672103 (provides space for transmission cooler)
Radiator Mount - 17117600538 (right side only)

Moving along to the auxiliary radiator, you would obviously need said radiator and bracket.

Aux Radiator - 17117628057
Frame - 17219452275

It appears a big difference is how the auxiliary oil cooler in the passenger wheel well is connected between M-Sport and Non variants. Non M-Sport has 17227639450 which is a single part for inlet/outlet pipes which goes directly into the oil cooler from the thermostat on the oil filter housing. On M Sport it seems there are three disparate inlet/outlet pipes and somehow an additional heat exchanger are connected between. From real OEM it looks like 17227639643 runs from the oil thermostat to the auxiliary oil cooler. And then it looks like some combination of two pipes [...]

So in essence, a nightmare to retrofit

[rlesko]

Originally Posted by Boostedphil698

So in essence, a nightmare to retrofit

Haha! Honestly, after working through most of the diagrams via real OEM I think it wouldn't actually be terribly hard to do if you had the coolant system drained.

I've already replaced my water pump once and refreshed a lot of hoses while I was doing so. If you decided to pursue this, once you had all the radiators, coolers, and heat exchangers mounted- these hoses are all so unique that I doubt you would be able to connect them in the wrong manner (assuming you had all the right hoses and pipes). Its easier to think about it as several different sub-circuits which end up "joining" together at the various heat exchangers.

The biggest issue IMO is cost, how are you sourcing all of this? This is easily $2000 from a BMW parts vendor. Is the performance increase worth that price? Are you willing to install a junkyard radiator on your car?

[Boostedphil698]

Originally Posted by rlesko

Haha! Honestly, after working through most of the diagrams via real OEM I think it wouldn't actually be terribly hard to do if you had the coolant system drained.

I've already replaced my water pump once and refreshed a lot of hoses while I was doing so. If you decided to pursue this, once you had all the radiators, coolers, and heat exchangers mounted- these hoses are all so unique that I doubt you would be able to connect them in the wrong manner (assuming you had all the right hoses and pipes). Its easier to think about it as several different sub-circuits which end up "joining" together at the various heat exchangers.

The biggest issue IMO is cost, how are you sourcing all of this? This is easily $2000 from a BMW parts vendor. Is the performance increase worth that price? Are you willing to install a junkyard radiator on your car?

I'd do a CSF radiator equivalent. Then do the OE aux cooler and aux pump. Money isn't the issue. Finding someone to do the work and know what they're doing is. I lucked out when I did my OE m sport bodykit and found a shop that did them. I ordered the kit from getbmwparts and saved like 2 grand but this would need to be pieced together. My dealer did my m sport wheel retrofit and that was a nightmare lol.

[Polo08816]

Originally Posted by rlesko

Just in case anyone is wondering what visionaut clipped in a screenshot earlier, its from this thread - https://f30.bimmerpost.com/forums/sh...65&postcount=7 (I was curious so I went digging)

So, I think with our collective minds we can solve this, along with some simple inferences.

For sake of brevity I won't list screws, bolts, or small items like that at this time. I'm assuming starting with an F3X car with N55 and auxiliary oil cooler.

First of all, it seems the primary radiator is different. There is a special radiator with different plumbing locations as well as space for the transmission radiator to wrap around. The left radiator mount appears to be the same for all variants (can reuse)

Radiator - 17118672103 (provides space for transmission cooler)
Radiator Mount - 17117600538 (right side only)

Moving along to the auxiliary radiator, you would obviously need said radiator and bracket.

Aux Radiator - 17117628057
Frame - 17219452275

It appears a big difference is how the auxiliary oil cooler in the passenger wheel well is connected between M-Sport and Non variants. Non M-Sport has 17227639450 which is a single part for inlet/outlet pipes which goes directly into the oil cooler from the thermostat on the oil filter housing. On M Sport it seems there are three disparate inlet/outlet pipes and somehow an additional heat exchanger are connected between. From real OEM it looks like 17227639643 runs from the oil thermostat to the auxiliary oil cooler. And then it looks like some combination of two pipes 17227626331 & 17227639644 plus the auxiliary heat exchanger 17217628058 must form the loop back.

The auxiliary water pump - 11517583965 is plumbed into this heat exchanger, and both are supported by this bracket - 17217628760 .

Now, the fun part. Lets start working our way through the hoses beginning at the primary radiator.

Coolant hose from primary to auxiliary radiator - 17127627101
Coolant return hose from auxiliary radiator to auxiliary water pump? - 17127627102

Coolant hose from auxiliary water pump to additional oil heat exchanger - 17127627103
Coolant Hose from additional heat exchanger back to primary radiator 17127627104

Now, in terms of what I can envision / infer from realOEM gets a bit fuzzy.

Transmission Radiator - 17117600535

is present, but I can't really fathom how its connected. I think it connects to the heat exchanger that is mounted directly on the radiator fan housing, but I'd have to be physically looking up at my car to imagine how the rest is connected. I know hoses 17127627105 and 17127627106 are involved but thats literally just grabbing part numbers from realOEM And pasting them here.

I reviewed the N55 technical training PDF and the cooling circuit there seems to not mirror our cars. I wonder if its for E series N55? You can there are quite a few different subtleties.

I haven't been able to determine which wiring harness needs to be changed yet to power and control the auxiliary water pump, but my guess is that it simply splits the primary water harness power / control - which means if you were crazy enough you could possibly tap into the wiring harness directly instead of replacing the whole thing. That is a total speculation though.

I was googling some pictures by part number and this came up - thanks to whoever decided to sell this assembly on eBay!



It really helped be 100% sure how some things are connected without inspecting an actual car.

Yeah, that was my recollection of how it was plumbed. Good that you've been able to confirm that.

[AmuroRay]

Originally Posted by Boostedphil698

I'd do a CSF radiator equivalent. Then do the OE aux cooler and aux pump. Money isn't the issue. Finding someone to do the work and know what they're doing is. I lucked out when I did my OE m sport bodykit and found a shop that did them. I ordered the kit from getbmwparts and saved like 2 grand but this would need to be pieced together. My dealer did my m sport wheel retrofit and that was a nightmare lol.

Don't do a CSF anything - their radiators work worse than stock and the oil coolers don't cool. DO88 or maybe Mishimoto.

[Boostedphil698]

Originally Posted by AmuroRay

Don't do a CSF anything - their radiators work worse than stock and the oil coolers don't cool. DO88 or maybe Mishimoto.

Based on?

[Polo08816]

Originally Posted by AmuroRay

Don't do a CSF anything - their radiators work worse than stock and the oil coolers don't cool. DO88 or maybe Mishimoto.

Originally Posted by Boostedphil698

Based on?

I have a CSF radiator and oil cooler. No issues so far on the track.

[AmuroRay]

Originally Posted by Boostedphil698

Based on?

temps increased with CSF radiator:
https://f87.bimmerpost.com/forums/sh....php?t=1525790

Marginal decrease (3f) in oil temps
https://www.2addicts.com/forums/show....php?t=1864339

Literally car got hotter with the CSF cooler:
https://f87.bimmerpost.com/forums/sh....php?t=2024707

[Boostedphil698]

Originally Posted by AmuroRay

temps increased with CSF radiator:
https://f87.bimmerpost.com/forums/sh....php?t=1525790

Marginal decrease (3f) in oil temps
https://www.2addicts.com/forums/show....php?t=1864339

Literally car got hotter with the CSF cooler:
https://f87.bimmerpost.com/forums/sh....php?t=2024707

These coolers are most likely a joke. I've also heard bad things about Mishimoto.

[visionaut]

If you’d like to really lower your temps, in a way you can notice daily, I can’t recommend the Mosselman oil thermostat for the outboard oil cooler enough. I’m super happy to never see 250F anymore. ‘Yeah yeah, hotter is more efficient blah blah blah’ - but performance is always better at 220F.

[Boostedphil698]

Originally Posted by visionaut

If you’d like to really lower your temps, in a way you can notice daily, I can’t recommend the Mosselman oil thermostat for the outboard oil cooler enough. I’m super happy to never see 250F anymore. ‘Yeah yeah, hotter is more efficient blah blah blah’ - but performance is always better at 220F.

I 100% will be doing that thermostat.

[AmuroRay]

Originally Posted by Boostedphil698

These coolers are most likely a joke. I've also heard bad things about Mishimoto.

I'll agree on both. I've just never been impressed by CSF - their intercooler was a rip (likely licensed from) ATM, but they fit a bit awkwardly and the hardware they came with was poor. 5 years later CSF pretended to care and sent owners literally $1 worth hardware, and started shipping it with their new intercoolers.

Their oil coolers also appear to be nothing special - the M235i's oil cooler is 13 rows - the M2 is 15? rows.

The CSF is 14+5 more on the rear where they do nothing but get hot air lol, it's a joke.

And you know it's a joke because they offer literally zero data on their products, and hope the end user will function as their advertising arm.

[Boostedphil698]

Originally Posted by AmuroRay

I'll agree on both. I've just never been impressed by CSF - their intercooler was a rip (likely licensed from) ATM, but they fit a bit awkwardly and the hardware they came with was poor. 5 years later CSF pretended to care and sent owners literally $1 worth hardware, and started shipping it with their new intercoolers.

Their oil coolers also appear to be nothing special - the M235i's oil cooler is 13 rows - the M2 is 15? rows.

The CSF is 14+5 more on the rear where they do nothing but get hot air lol, it's a joke.

And you know it's a joke because they offer literally zero data on their products, and hope the end user will function as their advertising arm.

100% agree. My intercooler is from ER and I think ER is an underrated brand. Their oil cooler kit is no joke either.

[Polo08816]

Originally Posted by Polo08816

I have a CSF radiator and oil cooler. No issues so far on the track.

Originally Posted by AmuroRay

temps increased with CSF radiator:
https://f87.bimmerpost.com/forums/sh....php?t=1525790

Marginal decrease (3f) in oil temps
https://www.2addicts.com/forums/show....php?t=1864339

Literally car got hotter with the CSF cooler:
https://f87.bimmerpost.com/forums/sh....php?t=2024707

Those are products that are not applicable to our chassis.

The "CSF radiator" is an intercooler. I've never had experience with that since my intercooler is the Wagner Tuning Evo 2 Competition.

The 2addicts thread oil cooler setup is nothing that I've ever seen before the F30 chassis.

The F87 thread is again, about an intercooler and not a coolant radiator.

Originally Posted by Boostedphil698

These coolers are most likely a joke. I've also heard bad things about Mishimoto.

Originally Posted by AmuroRay

I'll agree on both. I've just never been impressed by CSF - their intercooler was a rip (likely licensed from) ATM, but they fit a bit awkwardly and the hardware they came with was poor. 5 years later CSF pretended to care and sent owners literally $1 worth hardware, and started shipping it with their new intercoolers.

Their oil coolers also appear to be nothing special - the M235i's oil cooler is 13 rows - the M2 is 15? rows.

The CSF is 14+5 more on the rear where they do nothing but get hot air lol, it's a joke.

And you know it's a joke because they offer literally zero data on their products, and hope the end user will function as their advertising arm.

So the design of the oil coolers on the M cars is distinctly different than the non M cars. The M2 and CSF oil coolers are a single pass design - note that the CSF cooler (like the M2 oil cooler) require an additional half a quart of engine oil. They flow oil through in a way that is far more effective at lowering temps.