DCT Oil Thermostat Lines to DCT

Excers · 12-23-2019, 07:58 PM

I've been looking for the orings that connect the DCT oil thermostat to the side of the transmission. I have yet to been able to find them. They are slightly smaller then the orings used on the oil cooler lines. Anyone know the part number? Thanks

roastbeef · 12-23-2019, 08:03 PM

item #4 maybe?
https://www.realoem.com/bmw/enUS/sho...diagId=17_0436

Pig Farmer · 12-23-2019, 08:09 PM

P/N 17222245358

#4 on the diagram...

https://www.realoem.com/bmw/enUS/sho...diagId=17_0436

Excers · 12-23-2019, 08:09 PM

Quote:

Originally Posted by roastbeef

item #4 maybe?
https://www.realoem.com/bmw/enUS/sho...diagId=17_0436

Those are the same size as the ones on the the oil cooler lines. Slightly too large.

spammysammich · 06-13-2022, 05:31 PM

Sorry to bump an old post but does anybody know the answer to this? One of my lines from the tstat to the transmission is leaking

Excers · 06-13-2022, 05:42 PM

Quote:

Originally Posted by spammysammich

Sorry to bump an old post but does anybody know the answer to this? One of my lines from the tstat to the transmission is leaking

Check orings

spammysammich · 06-13-2022, 05:44 PM

Quote:

Originally Posted by Excers

Quote:

Originally Posted by spammysammich

Sorry to bump an old post but does anybody know the answer to this? One of my lines from the tstat to the transmission is leaking

Check orings

It's not, they're dry and serviced about 10k miles ago. The leak is coming from the aluminum junction block with the drip on it. I brake cleaned the whole area about 1k miles ago and confirmed the leak. Nothing else is weeping.

spammysammich · 06-13-2022, 05:47 PM

Unless there are o-rings sandwiched between the tstat and that line. But I can't find a hood exploded diagram of that area or the appropriate o-rings. The o rings that show up on searches are the ones held in place with the torx bolt and bracket.

spammysammich · 06-13-2022, 06:07 PM

I think I finally found them!

17211742636

https://www.realoem.com/bmw/enUS/sho...37#17222283582

Part number 11. For the lines going up to the heat exchanger. Now I just have to figure out how to actually service it without dropping the transmission

tdott · 06-13-2022, 07:40 PM

That system that has coolant goes to that box on top of the trans.

I think it's probably there to warm everything up faster but when things get hot I wonder if it makes things less efficient, ie coolant heating the DCT up.

spammysammich · 06-13-2022, 08:21 PM

There has already been somebody to report coolant and tranny fluid mixing in the exchanger but it seems to be a rare occurrence

Helmsman · 06-14-2022, 07:52 AM

Quote:

Originally Posted by tdott

That system that has coolant goes to that box on top of the trans.

I think it's probably there to warm everything up faster but when things get hot I wonder if it makes things less efficient, ie coolant heating the DCT up.

After heated up I hope the coolant also serve as cooler for the DCT fluid. Replaced the pump (aux water) the other day. Lets see if it helps to keep the DCT overheat away...

Lienrocs · 06-14-2022, 09:05 AM

I had the same leak. I replaced both lines and the t-stat. You can buy a tool to get the upper quick releases to let go. I 3D printed one because all the aluminum ones I could find were going to take several weeks to get to me. This was a few months ago though. It's a pretty simple job other than getting the lines to release from the cooler on top of the box.

spammysammich · 06-14-2022, 04:38 PM

Quote:

Originally Posted by Lienrocs

I had the same leak. I replaced both lines and the t-stat. You can buy a tool to get the upper quick releases to let go. I 3D printed one because all the aluminum ones I could find were going to take several weeks to get to me. This was a few months ago though. It's a pretty simple job other than getting the lines to release from the cooler on top of the box.

Did you have to drop the transmission? I can't really figure out how to get to that tstat without it at least tilted down.

Lienrocs · 06-14-2022, 06:39 PM

Quote:

Originally Posted by spammysammich

Quote:

Originally Posted by Lienrocs

I had the same leak. I replaced both lines and the t-stat. You can buy a tool to get the upper quick releases to let go. I 3D printed one because all the aluminum ones I could find were going to take several weeks to get to me. This was a few months ago though. It's a pretty simple job other than getting the lines to release from the cooler on top of the box.

Did you have to drop the transmission? I can't really figure out how to get to that tstat without it at least tilted down.

I did not have to drop the transmission. It was fiddly but not impossible.

spammysammich · 06-14-2022, 06:43 PM

Quote:

Originally Posted by Lienrocs

Quote:

Originally Posted by spammysammich

Quote:

Originally Posted by Lienrocs

I had the same leak. I replaced both lines and the t-stat. You can buy a tool to get the upper quick releases to let go. I 3D printed one because all the aluminum ones I could find were going to take several weeks to get to me. This was a few months ago though. It's a pretty simple job other than getting the lines to release from the cooler on top of the box.

Did you have to drop the transmission? I can't really figure out how to get to that tstat without it at least tilted down.

I did not have to drop the transmission. It was fiddly but not impossible.

So were you able to establish the root cause for the leak? I'm almost 100% sure mine is the o-ring between the DCT body and the line that gets pinched into place when the tstat is bolted to the DCT.
I tried to blast the whole area with brake cleaner and the leak returned at the rectangularish block, not at the rubber/metal junction of the line.

Lienrocs · 06-14-2022, 06:48 PM

Quote:

Originally Posted by spammysammich

Quote:

Originally Posted by Lienrocs

Quote:

Originally Posted by spammysammich

Quote:

Originally Posted by Lienrocs

I had the same leak. I replaced both lines and the t-stat. You can buy a tool to get the upper quick releases to let go. I 3D printed one because all the aluminum ones I could find were going to take several weeks to get to me. This was a few months ago though. It's a pretty simple job other than getting the lines to release from the cooler on top of the box.

Did you have to drop the transmission? I can't really figure out how to get to that tstat without it at least tilted down.

I did not have to drop the transmission. It was fiddly but not impossible.

So were you able to establish the root cause for the leak? I'm almost 100% sure mine is the o-ring between the DCT body and the line that gets pinched into place when the tstat is bolted to the DCT.
I tried to blast the whole area with brake cleaner and the leak returned at the rectangularish block, not at the rubber/metal junction of the line.

I think it was an o ring leak. I spent a little time trying to diagnose the issue but I had a track day coming up so I replaced the send and return lines to the small cooler on top of the box and I replaced the t-stat as well.

spammysammich · 06-14-2022, 06:52 PM

Fair enough, those lines are known to leak. This won't be that fun even with a quickjack. I might see if I can get some time on a lift. It's not a gusher but bad enough to leave a puddle when my AC condensation drains into the cover panel.

spammysammich · 11-03-2022, 08:14 PM

@deansbimmer is there any way of changing the #11 o-rings in this diagram without a drain and fill service on the DCT? The o-ring at the #12 line sandwiched between the thermostat and transmission housing is now leaking enough to blow back to the muffler and rear diff.

amrazM · 11-04-2022, 05:12 AM

When you pull the thermostat out not all of the fluid will leak out, just what is in the thermostat and in the case casting at that point up.

spammysammich · 11-04-2022, 09:25 AM

Quote:

Originally Posted by amrazM

When you pull the thermostat out not all of the fluid will leak out, just what is in the thermostat and in the case casting at that point up.

Thanks. Looks like I'll have to tilt the transmission down a bit to get enough space, then separate the thermostat from the transmission. Am I on the right track?

I did a more thorough inspection of the case and found one of the side panel T30 had backed off a few turns or was missed at the last major service.

amrazM · 11-04-2022, 12:53 PM

Quote:

Originally Posted by spammysammich

Thanks. Looks like I'll have to tilt the transmission down a bit to get enough space, then separate the thermostat from the transmission. Am I on the right track?

I did a more thorough inspection of the case and found one of the side panel T30 had backed off a few turns or was missed at the last major service.

im sure you can get in and get to that screw on the thermostat.

ive seen those t30s on the side cover run loose on my own car.l

12-23-2019, 07:58 PM	#1
Excers Private 33 Rep 68 Posts Drives: e92 M3 Join Date: May 2019 Location: Arizona iTrader: (0)	DCT Oil Thermostat Lines to DCT I've been looking for the orings that connect the DCT oil thermostat to the side of the transmission. I have yet to been able to find them. They are slightly smaller then the orings used on the oil cooler lines. Anyone know the part number? Thanks Attached Images
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12-23-2019, 08:03 PM	#2
roastbeef Lieutenant General 11586 Rep 12,726 Posts Drives: E92 M3 Join Date: Nov 2010 Location: Orange County, CA iTrader: (4)	item #4 maybe? https://www.realoem.com/bmw/enUS/sho...diagId=17_0436 __________________ Instagram; @roastbeefmike
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12-23-2019, 08:09 PM	#3
Pig Farmer Major 340 Rep 1,293 Posts Drives: E92M Join Date: May 2010 Location: Florida iTrader: (0)	P/N 17222245358 #4 on the diagram... https://www.realoem.com/bmw/enUS/sho...diagId=17_0436
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06-13-2022, 05:31 PM	#5
spammysammich Major 1582 Rep 1,104 Posts Drives: 2009 E92 M3 Dakar Yellow II Join Date: Oct 2021 Location: Edmonds, WA iTrader: (0) Garage List 2009 BMW M3 [10.00]	Sorry to bump an old post but does anybody know the answer to this? One of my lines from the tstat to the transmission is leaking Attached Images
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06-13-2022, 05:47 PM	#8
spammysammich Major 1582 Rep 1,104 Posts Drives: 2009 E92 M3 Dakar Yellow II Join Date: Oct 2021 Location: Edmonds, WA iTrader: (0) Garage List 2009 BMW M3 [10.00]	Unless there are o-rings sandwiched between the tstat and that line. But I can't find a hood exploded diagram of that area or the appropriate o-rings. The o rings that show up on searches are the ones held in place with the torx bolt and bracket.
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06-13-2022, 06:07 PM	#9
spammysammich Major 1582 Rep 1,104 Posts Drives: 2009 E92 M3 Dakar Yellow II Join Date: Oct 2021 Location: Edmonds, WA iTrader: (0) Garage List 2009 BMW M3 [10.00]	I think I finally found them! 17211742636 https://www.realoem.com/bmw/enUS/sho...37#17222283582 Part number 11. For the lines going up to the heat exchanger. Now I just have to figure out how to actually service it without dropping the transmission
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06-13-2022, 07:40 PM	#10
tdott Brigadier General 3943 Rep 3,988 Posts Drives: M3 Join Date: Nov 2010 Location: South FL / 6ix iTrader: (4)	That system that has coolant goes to that box on top of the trans. I think it's probably there to warm everything up faster but when things get hot I wonder if it makes things less efficient, ie coolant heating the DCT up. Last edited by tdott; 06-13-2022 at 09:20 PM..
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06-13-2022, 08:21 PM	#11
spammysammich Major 1582 Rep 1,104 Posts Drives: 2009 E92 M3 Dakar Yellow II Join Date: Oct 2021 Location: Edmonds, WA iTrader: (0) Garage List 2009 BMW M3 [10.00]	There has already been somebody to report coolant and tranny fluid mixing in the exchanger but it seems to be a rare occurrence
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06-14-2022, 09:05 AM	#13
Lienrocs Captain 703 Rep 867 Posts Drives: E92 M3, M4 GTS, HP4 Join Date: May 2017 Location: Austin iTrader: (3)	I had the same leak. I replaced both lines and the t-stat. You can buy a tool to get the upper quick releases to let go. I 3D printed one because all the aluminum ones I could find were going to take several weeks to get to me. This was a few months ago though. It's a pretty simple job other than getting the lines to release from the cooler on top of the box.
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06-14-2022, 06:52 PM	#18
spammysammich Major 1582 Rep 1,104 Posts Drives: 2009 E92 M3 Dakar Yellow II Join Date: Oct 2021 Location: Edmonds, WA iTrader: (0) Garage List 2009 BMW M3 [10.00]	Fair enough, those lines are known to leak. This won't be that fun even with a quickjack. I might see if I can get some time on a lift. It's not a gusher but bad enough to leave a puddle when my AC condensation drains into the cover panel.
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11-03-2022, 08:14 PM	#19
spammysammich Major 1582 Rep 1,104 Posts Drives: 2009 E92 M3 Dakar Yellow II Join Date: Oct 2021 Location: Edmonds, WA iTrader: (0) Garage List 2009 BMW M3 [10.00]	@deansbimmer is there any way of changing the #11 o-rings in this diagram without a drain and fill service on the DCT? The o-ring at the #12 line sandwiched between the thermostat and transmission housing is now leaking enough to blow back to the muffler and rear diff. Attached Images
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11-04-2022, 05:12 AM	#20
amrazM mTekMods 2142 Rep 2,901 Posts Drives: like a granny. Join Date: Jan 2010 Location: Manhatan iTrader: (1)	When you pull the thermostat out not all of the fluid will leak out, just what is in the thermostat and in the case casting at that point up. __________________ 2011 Frozen Black/Fox Red E90 M3 650+WHP G-Power Supercharged First DCT to Manual Conversion Worldwide KW CS, BBS RI-A, BW Headers, Snow 2.5
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